U.S. patent application number 12/653464 was filed with the patent office on 2010-06-17 for polishing head for the zonal machining of optical spectacle surfaces.
This patent application is currently assigned to SCHNEIDER GMBH & CO. KG. Invention is credited to Helwig Buchenauer, Stephan Huttenhuis, Klaus Kramer, Gunter Schneider.
Application Number | 20100151772 12/653464 |
Document ID | / |
Family ID | 41796406 |
Filed Date | 2010-06-17 |
United States Patent
Application |
20100151772 |
Kind Code |
A1 |
Schneider; Gunter ; et
al. |
June 17, 2010 |
Polishing head for the zonal machining of optical spectacle
surfaces
Abstract
A polishing head for spectacle surfaces with a basic body for
attachment to a polishing spindle, with an elastic supporting part
for a polishing film which is or can be attached, wherein the
supporting part comprises a recess with a wall surface and a depth
t, and the polishing film comprises at least one hole, wherein the
hole forms an access to the recess, wherein the polishing film
comprises in addition to the hole at least one further hole, which
is arranged in the area of an edge of the recess and is at a radial
distance a from the hole, wherein the further hole forms an outlet
channel for polishing agent from out of the recess or the wall
surface is raised at least over one section of the depth t, and/or
with reference to a circumference, at least in segments in relation
to the rotational axis D at an angle .alpha., and/or the supporting
part comprises at least one groove which is provided in the front
side with a groove base and a depth t1, which is connected to the
recess and/or the supporting part comprises at least one channel
with an opening which connects the recess and the front side. A
method in which a reserve supply of polishing agent is filled into
the recess in the supporting part prior to the conjoining of the
polishing head and the surface to be polished.
Inventors: |
Schneider; Gunter; (Marburg,
DE) ; Buchenauer; Helwig; (Dautphetal-Buchenau,
DE) ; Huttenhuis; Stephan; (Marburg, DE) ;
Kramer; Klaus; (Dautphetal-Friedensdorf, DE) |
Correspondence
Address: |
HUDAK, SHUNK & FARINE, CO., L.P.A.
2020 FRONT STREET, SUITE 307
CUYAHOGA FALLS
OH
44221
US
|
Assignee: |
SCHNEIDER GMBH & CO. KG
STEFFENBERG
DE
|
Family ID: |
41796406 |
Appl. No.: |
12/653464 |
Filed: |
December 15, 2009 |
Current U.S.
Class: |
451/42 ; 451/259;
451/450 |
Current CPC
Class: |
B24D 13/147 20130101;
B24B 13/01 20130101; B24D 13/18 20130101 |
Class at
Publication: |
451/42 ; 451/259;
451/450 |
International
Class: |
B24B 13/01 20060101
B24B013/01; B24B 55/02 20060101 B24B055/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 16, 2008 |
DE |
10 2008 062 097.1 |
Claims
1. A polishing head for the zonal machining of optical spectacle
surfaces, comprising: a basic body which comprises a rotational
axis D for attachment to a polishing spindle, with an elastic
supporting part which is arranged on the basic body, on which a
polishing film is arranged, wherein the supporting part comprises a
recess of a depth t and the polishing film comprises at least one
hole, wherein the hole forms an access to the recess, wherein the
polishing film comprises, in addition to the hole, at least one
further hole which is arranged in an area of an edge of the recess,
and which is at a radial distance a from the hole, wherein the
further hole forms an outlet channel for polishing agent from out
of the recess.
2. A polishing head for the zonal machining of optical spectacle
surfaces, comprising: a basic body which comprises a rotational
axis D for attachment to a polishing spindle and with an elastic
supporting part which is arranged on the basic body, which
comprises a front side for attaching a polishing film, wherein the
supporting part has a recess which comprises a wall surface with a
depth t, wherein the wall surface is raised at least over a part of
a depth t and/or in relation to a circumference at least in
segments in relation to the rotational axis D at an angle .alpha.,
wherein the wall surface is designed without a re-entrant angle
and/or the supporting part comprises at least one groove which is
provided in the front side with a groove base and a depth t1, which
connects to the recess, wherein the depth t1 is less than the depth
t, and/or the supporting part comprises at least one channel which
connects the recess and the front side with an opening, wherein the
opening of the channel is provided at a depth t2 of the recess with
reference to a central axis M of the channel.
3. The polishing head according to claim 2, with a polishing film
which is attached to the supporting part, or a polishing film
wherein the polishing film comprises at least one hole, wherein the
hole forms an access to the recess and the polishing film comprises
an inner side which faces or can face the supporting part and an
outer side which can be placed on the optical surface, and that the
polishing film also comprises, in addition to the hole, at least
one further hole with a radial distance a from the hole, which is
arranged in the area of an edge of the recess and/or in the area of
the groove and/or in the area of an opening of the channel, wherein
the further hole forms an outflow channel for polishing agent from
out of the recess, the groove and/or the opening.
4. The polishing head according to claim 2, wherein the central
axis M of the channel comprises with the rotational axis D an angle
.beta. between 25.degree. and 60.degree..
5. The polishing head according to claim 2, wherein the channel is
curved or parabolic, wherein the angle .beta. varies over the
length of the channel.
6. The polishing head according to claim 1, wherein the polishing
film comprises an inner side which faces or can face the supporting
part and an outer side which can be placed on the optical surface,
wherein the polishing film comprises in addition to the hole at
least one groove which is provided on the inner side with a groove
base, and comprises on the outer side at least one recess which
partially opens the groove base towards the outer side and which is
at a distance d from the hole, wherein the groove with the recess
forms an outflow channel for polishing agent from out of the
recess.
7. The polishing head according to claim 1, wherein the polishing
film comprises a first function area F1 and corresponding means for
a) a lid function in partial areas of the edge of the recess by
means of an overhang b) an onward transportation function for
polishing agent from out of the recess radially outwards through
the groove and/or in the axial direction through the further
hole.
8. The polishing head according to claim 1, wherein the polishing
film comprises a second function area F2 and corresponding means
for the outlet function for polishing agent towards the outer side
through the further hole and/or through the recess.
9. The polishing head according to claim 7, wherein the polishing
film comprises a lower section with the inner side and an upper
section with the outer side, wherein the first function area F1 is
assigned to the lower section and the second function area F2 is
assigned to the upper section.
10. The polishing head according to claim 1 wherein the recess
comprises a volume which is at least 0.3 ml.
11. The polishing head according to claim 1, wherein the recess is
funnel and/or cup-shaped, wherein the wall surface of the recess
comprises a straight or parabolic limitation line B with reference
to the cross-section view.
12. The polishing head according to claim 1, wherein the recess or
at least the funnel and/or cup-shaped part of the recess is
segmented into several partial segments with reference to the
circumferential direction U.
13. The polishing head according to claim 1, wherein the basic body
comprises a central polishing means channel.
14. A method for polishing optical spectacle surfaces with a zonal
polishing tool, consisting of a polishing spindle and a polishing
head arranged on it, which is formed from a basic body for
attachment to the polishing spindle and an elastic supporting part
which is arranged on the basic body with a recess and a polishing
film which is attached to the supporting part, comprising the steps
of: filling prior to conjoining the polishing head and the surface
to be polished, a reserve supply of polishing agent into the recess
in the supporting part, and/or feeding polishing agent via the
polishing agent channel.
15. A method according to claim 14, wherein this filling procedure
is repeated at least once during the polishing process of the one
spectacle surface.
16. The polishing head according to claim 10, wherein the recess
comprises a volume which is at least 0.6 ml.
17. The polishing head according to claim 3, wherein the polishing
film comprises an inner side which faces or can face the supporting
part and an outer side which can be placed on the optical surface,
wherein the polishing film comprises in addition to the hole at
least one groove which is provided on the inner side with a groove
base, and comprises on the outer side at least one recess which
partially opens the groove base towards the outer side and which is
at a distance d from the hole, wherein the groove with the recess
forms an outflow channel for polishing agent from out of the
recess.
18. The polishing head according to claim 17, wherein the polishing
film comprises a first function area F1 and corresponding means for
a) a lid function in partial areas of the edge of the recess by
means of an overhang b) an onward transportation function for
polishing agent from out of the recess radially outwards through
the groove and/or in the axial direction through the further
hole.
19. The polishing head according to claim 18, wherein the polishing
film comprises a second function area F2 and corresponding means
for the outlet function for polishing agent towards the outer side
through the further hole and/or through the recess.
20. The polishing head according to claim 19, wherein the polishing
film comprises a lower section with the inner side and an upper
section with the outer side, wherein the first function area F1 is
assigned to the lower section and the second function area F2 is
assigned to the upper section.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a polishing head for the zonal
machining of optical spectacle surfaces with a basic body which
comprises a rotational axis D for attachment to a polishing
spindle, with an elastic supporting part which is arranged on the
basic body, on which a polishing film is arranged, wherein the
supporting part comprises a recess of the depth t and the polishing
film comprises at least one hole, wherein the hole forms an access
to the recess.
[0002] Furthermore, the invention relates to a polishing head for
the zonal machining of optical spectacle surfaces with a basic body
which comprises a rotational axis D for attachment to a polishing
spindle and with an elastic supporting part which is arranged on
the basic body which comprises a front side for attaching a
polishing film, wherein the supporting part comprises a central
recess with a depth t and with a wall surface.
[0003] The invention also relates to a method for polishing optical
spectacle surfaces with a zonal polishing tool, consisting of a
polishing spindle and a polishing head arranged thereon, which is
formed by a basic body for attachment to the polishing spindle and
an elastic supporting part which is arranged on the basic body with
a recess, and a polishing film which is attached to the supporting
part.
BACKGROUND OF THE INVENTION
[0004] A polishing plate for a tool for the fine machining of
optical surfaces on spectacle lenses is already known from DE 10
2005 010 583 A1. This polishing plate comprises a supporting body
to which a foam layer is attached, on which a polishing film rests.
The polishing film is equipped in a central area with at least one
opening. The opening ensures during machining that pressure is
compensated and provides fluid polishing agent from inside the foam
layer, as a result of which improved rinsing and cooling of
otherwise neglected polishing plate areas is achieved.
[0005] The recess within the supporting part known from DE 10 2005
010 583 A1 is designed to serve as a reservoir for fluid polishing
agent during machining which has been stored or absorbed in the
foam, i.e. in the supporting part itself, and which when the
supporting part is tumbled or compressed enters the recess starting
from the pores. From there, it is to be fed to the polishing
process via the opening in the polishing film. A separate filling
of the recess according to the invention prior to attachment of the
tool is not provided according to the principle of the prior art.
To a far greater extent, it is common that the surface to be
polished on the one hand, and the polishing head on the other, is
provided after attachment onto the surface to be polished with
polishing agent from the side, which is then to be fed inwards due
to the capillary function of the supporting part.
[0006] The opening in the polishing film accordingly serves to
transport onward fluid polishing agent from the inside of the foam
layer. The foam layer itself comprises a recess in the area of the
opening in the polishing film which serves during machining as a
reservoir for the fluid polishing agent.
[0007] U.S. Pat. No. 3,128,580 describes a grinding and polishing
machine with a grinding an polishing head which comprises several
grooves which serve to more effectively transport cooling agent to
the workpiece surface which is to be machined. Here, the grooves
are provided within the grinding and polishing coating, wherein the
respective groove is assigned a groove-shaped recess within the
basic body of the grinding and polishing head. Furthermore, within
the grinding and polishing coating, a centric, circular recess is
provided which is assigned a corresponding, pot-shaped recess
within the basic body for retaining cooling agent. According to the
exemplary embodiment in FIG. 11, the grooves or associated
groove-shaped recesses run through into the area of the centric
recess or opening, wherein a space is provided between the groove
and the centric recess. As can clearly be seen in FIGS. 10 and 12,
there is however no through-flow connection between the centric
recess and the respective groove or groove-shaped recess. According
to the exemplary embodiments in FIGS. 4, 8 and 9, there is a
through-flow connection between the centric recess and the groove
or groove-shaped recess, but there is no space between the
groove-shaped recess and the centric recess.
[0008] The different recesses serve as a retaining reservoir for
cooling agent which is probably designed to exit the recesses
upwards towards the workpiece in stages during the process. No
direct onward transportation between the different recesses is
described.
SUMMARY OF THE INVENTION
[0009] The object of the invention is to design and arrange a
polishing film or polishing head for optical spectacle surfaces in
such a manner that improved transportation of polishing agent
between the polishing film and the surface to be machined is
guaranteed.
[0010] The object is attained according to the invention by means
of the objects or method according to the claims.
[0011] The fact that the polishing film comprises in addition to
the hole at least one further or separate hole which is arranged in
the area of an edge of the recess and which is at a radial distance
a from the hole, results in an outlet for polishing agent from out
of the recess. The additional or separate hole can also be formed
as a groove-shaped extension of the central hole. The
aforementioned distance relates in this case to the respective
radial outside edge of the central hole on the one hand and the
groove-shaped extension on the other. Due to the centrifugal forces
which are created with the rotation, the polishing agent is forced
outwards or upwards in the edge area of the recess, regardless of
the form of the polishing agent. Due to the additional hole or
groove-shaped extension according to the invention in the edge area
of the recess, in the direction of which the polishing agent is
forced upwards or outwards due to the centrifugal forces, the
polishing agent can exit from the hole and thus be incorporated or
distributed between the polishing film and the surface to be
machined. The hole or groove-shaped extension is here designed in
terms of its size or diameter in accordance with the required
volume flow. This also applies to the number of holes or
groove-shaped extensions which are arranged over the circumference.
When polishing optical spectacle surfaces or aspherical surfaces,
it should be assumed that the polishing film rises up from the
polishing surface during the polishing process, as a result of
which the additional hole according to the invention is not
continuously closed by the surface to be machined. Accordingly, the
separate hole according to the invention is significantly smaller
in design than the centric opening already known from the prior
art, taking into account the torques to be achieved during the
polishing process, i.e. taking into account the anticipated volume
flow on the one hand and the viscosity of the polishing agent on
the other. The diameter of the hole according to the invention is
between 0.2 and 4 mm.
[0012] The wall surface which is raised at least over one part of
the depth t and/or in relation to a circumference at least in
segments in relation to the rotational axis D at an angle .alpha.
without a re-entrant angle, guarantees improved transportation of
polishing agent in the radial and axial direction from out of the
recess by using the centrifugal forces which are created during
machining. This feature can be provided as an alternative or as a
supplement to the transportation of the polishing agent flow.
[0013] Here, it is provided that the recess opens towards a side
facing the polishing surface, due to the raising of the wall
surface, as is shown in the exemplary embodiments in FIGS. 2, 4,
5a, 5b, 5c, 6a and 8, so that greater quantities of polishing agent
are transported to the edge of the recess.
[0014] The polishing film to be arranged usually comprises a
centric hole, wherein the hole forms an access to the recess for
the purpose of filling. With the raising of the wall surface, an
increased share of force is applied onto the polishing agent which
rotates with the polishing plate in the axial direction to the
rotational axis, so that said agent is significantly more
effectively transported out of the recess, if necessary upwards via
a channel to a polishing film or outlets which is or are to be
provided there.
[0015] The groove which is provided in the free front side of the
supporting part and which leads to the recess in the flow
connection, with a groove base and a depth t1, guarantees an
increased polishing agent flow from out of the recess at a height
below the polishing film. This feature can be provided as an
alternative or supplement to the transportation of the polishing
agent flow. The polishing agent can thus exit from out of the
recess via the groove below the polishing film to be applied in the
radial direction of the groove, and be transported onward by means
of the groove.
[0016] The depth t1 of the groove is smaller than the depth t of
the recess. The groove thus forms a channel in the supporting part
which is open to one side, which is at least partially closed by
the polishing film with the exception of an outlet opening or an
exit. If the depth t1 of the groove is the same as the depth t of
the recess, the recess is segmented, as is described below. This
also applies when the depth t of the recess or the depth t1 of the
groove varies over the radius.
[0017] Alternatively or as a supplement, the supporting part can
comprise at least one channel with an opening which connects the
recess and the front side, wherein the opening of the channel is
provided in a depth t2 of the recess or close to the floor in
relation to a central axis M of the channel. The polishing agent
can exit from out of the recess close to the floor via the channel.
The channel thus represents a closed variant of a groove, the depth
t1 of the groove base of which varies with the radius.
[0018] As an alternative to the case described in the introduction,
it can be provided that the recess, due to a reverse raising of the
wall surface in the opposite direction, thus opens towards the
basic body, and accordingly is not formed without a re-entrant
angle. In this case, the polishing agent, due to the centrifugal
forces, is transported in greater quantities into an opening of a
channel close to the floor, or into the channel which connects the
recess or area of the recess which is close to the floor with a
front side of the supporting part.
[0019] When a polishing head of the type described above is used,
with which for the purpose of usage on the supporting part, a
polishing film can be attached with at least one hole, wherein the
hole forms an access to the recess, it can be advantageous when the
polishing film comprises an inner side which faces or can be faced
towards a supporting part, and an outer side which can be placed
onto the optical surface, and when the polishing film comprises, in
addition to the hole, at least one further hole which is arranged
at a radial distance a to the hole, which is arranged in the area
of an edge of the recess and/or in the area of the groove and/or in
the area of an opening of the channel, wherein the further hole
forms an outflow channel for polishing agent from out of the
recess, from out of the groove and/or from out of the opening. As a
result, the advantages described above relating to the
transportation of polishing agent to the surface to be machined are
achieved.
[0020] If the central axis M of the channel comprises an angle
.beta. of between 25.degree. and 60.degree. with the rotational
axis D, the polishing agent is transported in an optimum manner
outwards and upwards due to the centrifugal forces which are
created during machining. The position ultimately depends on the
required outlet site on the front side, or out of the polishing
film which rests on it, and on the diameter of the supporting part.
Preferably, the channel opens out in the recess close to the
floor.
[0021] The channel can also be curved or parabolic, so that the
angle .beta. varies over the length of the channel or over the
radius of the polishing head. The channel can be flatter close to
the rotational axis, which despite lower centrifugal forces
facilitates the transportation of the polishing agent. With a
greater distance from the rotational axis D, the channel can be
steeper, which initially impairs the transportation of the
polishing agent. Due to the centrifugal forces which increase with
the radius, this disadvantage is compensated, however.
[0022] It can also be advantageous when the polishing film
comprises an inner side which faces or can face the supporting
part, and an outer side which can be placed on the optical surface,
wherein the polishing film also comprises, in addition to the hole,
at least one groove with a groove base which is provided on the
inner side, and at least one recess on the outer side which
partially opens the groove base in the direction of the outer side,
and which comprises a distance d from the hole. The groove here
preferably runs in the radial direction. It connects an inflow for
polishing agent, preferably the edge area of the recess with the
recess which lies further outwards in the radial direction, so that
polishing agent is guided, starting from the recess in the
supporting part, through the groove to the recess and thus between
the polishing film and a surface to be polished. The open side of
the groove is closed when the polishing film is placed onto the
supporting part, and is thus formed as a channel. The groove in the
polishing film can here be stamped and/or produced as part of the
forming process of the polishing film. It is also feasible for the
groove to be formed after the forming process of the polishing film
using a cutting machining process. These features can be provided
as an alternative or supplement to the facilitation of the
polishing agent flow.
[0023] Here, it can be advantageous when the groove in the
supporting part, the groove in the polishing film and/or the
channel in the supporting part runs in the radial direction to the
rotational axis D. The length or radial extension of the groove or
of the channel also depends on how far the recess according to the
invention or the hole according to the invention on the outer side
of the polishing film is removed from the central hole provided in
the polishing film.
[0024] As an alternative or supplement, it is advantageous when the
central hole of the polishing film forms an access to the recess
and the groove of the polishing film, the groove of the supporting
part and/or the channel for the supporting part forms an outflow
channel for polishing agent from out of the recess, wherein the
polishing film comprises a hole which for the purpose of the exit
of polishing agent connects to the groove of the supporting part
and/or the channel of the supporting part. As has already been
described, the supporting part of the polishing head in connection
with the polishing film described above forms an outflow channel
for polishing agent stored in the recess of the supporting part,
which is arranged below the polishing film. By means of the groove,
the polishing agent is guided radially outwards over any distance
required through to the outlet hole, starting from the recess or an
edge of the recess and due to the displacement effect created with
the rotation, in order to exit outwards there. The size or
dimension of the groove or channel and the size of the connecting
hole in the polishing film is also selected according to the
required polishing agent flow, depending on the polishing agent
pressure, which varies according to the viscosity of the polishing
agent and the torque.
[0025] It can be of particular significance to the present
invention when the hole in the polishing film comprises a diameter
d1 and the recess on the edge comprises a diameter d2, wherein the
diameter d1 is smaller than the diameter d2 and the polishing film
protrudes over the edge of the recess, and the recess at least
partially closes in the edge area in the axial direction. Thus, the
edge area of the recess in which the polishing agent would exit
upwards and/or to the side due to the centrifugal forces, is closed
by the polishing film. The polishing film can accordingly not exit
there, or only into the holes and/or grooves which are provided as
described above, which serve a defined onward transportation and
elimination of polishing agent towards the outer surface. The
protrusion which is thus formed is between 15% and 90%, preferably
between 20% and 60% of the half diameter d2.
[0026] In connection with the design and arrangement according to
the invention, it can be advantageous when the polishing film
comprises a first function area F1 and corresponding means which
guarantees a lid function in partial areas of the edge of the
recess due to a protrusion and an onward transportation function
for polishing agent radially outwards from out of the recess
through the groove and/or in the axial direction through the
additional hole. Due to the groove, an onward transportation
function for the polishing agent is also guaranteed which acts in
the axial direction. However, the radial onward transportation
function is of primary significance due to the length of the
groove. The lid function guarantees the retention of polishing
agent, so that the restricted volume of polishing agent can be
defined within the scope of the onward transportation function, and
thus transported onwards in doses, and ultimately relinquished to
the required areas of the polishing agent foil. The onward
transportation function is guaranteed on the side of the supporting
part by the groove or channel in the supporting part.
[0027] It can furthermore be advantageous when the polishing film
comprises a second function area F2 and corresponding means which
guarantees the outlet function for polishing agent towards the
outer side through the additional hole on the edge of the recess,
through the hole which leads to the groove or channel in the
supporting part and/or through the recess which leads to the groove
in the polishing film. The second function area guarantees the
required outflow of polishing agent to the positions which can be
freely selected on the outer side of the polishing film.
[0028] It can also be advantageous when the polishing film
comprises a lower section with the inner side and an upper section
with the outer side, wherein the first function area F1 is assigned
to the lower section, and the second function area F2 is assigned
to the upper section. The polishing film can here be single, dual
or triple-layered for the purpose of creating an onward
transportation system according to requirements.
[0029] For this purpose, it can alternatively also be advantageous
when the lower section and the upper section are formed as a single
piece and/or are of the same material, or when the lower section
and the upper section form separate components. If two different
components are present, the lower section can also be assigned a
stiffening function, so that the adaptability of the polishing film
in connection with the flexible support is restricted in the
downwards direction, i.e. towards smaller radii.
[0030] Here, it can be advantageous when the recess comprises a
volume which is at least 0.3 ml or 0.4 ml or 0.5 ml or 0.6 ml. The
main function of the supporting part continues to be to support the
polishing film when the surface is being polished. The support
function is reduced overall or is eliminated completely in the area
of the recess according to the size of the centric recess which is
designed as a polishing agent reserve supply, so that the radial
extension of the recess must ultimately also be restricted. Taking
into account the height of the supporting part, i.e. the depth of
the recess, a required storage volume for polishing agent, albeit
one which is restricted in terms of its upper level, can thus be
achieved.
[0031] Ultimately, it can be advantageous when the recess is formed
as a funnel and/or cup and/or truncated cone, wherein the raised
part of the wall surface of the recess is level or flat. Flat or
level wall surfaces can be produced somewhat more easily due to the
tools available. The funnel and/or cup-shaped design of at least
the upper section of the recess improves the polishing agent
pressure in the upper edge area of the recess which is created with
the rotation, as is mentioned above.
[0032] For this purpose, it can be advantageous when the raised
part of the wall surface of the recess comprises a straight or
parabolic limitation line B which comprises an angle .alpha. with
the rotational axis. With the parabolic limitation line B, the
angle .alpha. varies in relation to the depth t. With the varying
angle .alpha., the distance between the surface of the rotational
axis when selecting the angle .alpha. can be taken into account,
i.e. with surface areas at a lower distance from the rotational
centre or to the rotational axis D, the angle .alpha. is
correspondingly wide, and with surfaces at a greater distance from
the rotational centre, it is correspondingly smaller, as is shown
in the example in FIG. 5c. Thus, excess outflow or polishing agent
pressure in the areas at a greater distance from the rotational
centre is avoided, while at the same time, the depth t of the
recess is bridged.
[0033] Ultimately, it can be advantageous when the recess or at
least the funnel and/or cup-shaped part of the recess is segmented
in relation to the circumferential direction U into several partial
segments. The lack of support by the supporting part which results
from the recess is at least partially rectified with a segmented
structure of the funnel-shaped parts of the recess. On the one
hand, this guarantees a somewhat higher volume for the polishing
fluid, while on the other, guaranteeing a support function which is
dependent on the size of the segments or the extensions of the
recess.
[0034] Finally, it can be advantageous when the basic body
comprises a central polishing agent channel. The polishing head can
be supplied with polishing agent via the polishing agent channel,
which is provided or fed via the polishing spindle. The polishing
agent can be transported via the polishing agent channel into the
recess and transported from there in the manner described
above.
[0035] Due to the fact that in terms of the method, a reserve
supply of polishing agent is filled into the recess in the
supporting part prior to conjoining the polishing head and the
surface to be polished, a significantly greater reserve supply of
polishing agent results, which during the subsequent machining is
transported using the means described above between the polishing
film and the surface to be processed. The same applies accordingly
when polishing agent is fed via the polishing agent channel. Since
the quantities which can be fed via the polishing agent channel are
significantly greater, good cooling effects can also be achieved
alongside reproducible results.
[0036] For the method, it is advantageous when the filling
procedure is repeated during the polishing process of one spectacle
surface several time, if necessary, between two and ten times. The
overall volume of polishing agent which is available in general for
one polishing process can be increased by the appropriate factor,
on the basis of the aforementioned volumes of the recess, which
improves the quality of the polishing process and above all,
however, the reproducibility of the polishing process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Further advantages and details of the invention are
explained in the patent claims and in the description and are
illustrated in the figures, in which:
[0038] FIG. 1 shows a perspective view of the polishing head with a
polishing film;
[0039] FIG. 2 shows a cross-section view from FIG. 1;
[0040] FIG. 3 shows a top view of the polishing head as a schematic
diagram;
[0041] FIG. 4 shows a cross-section view according to section A-A
of FIG. 3;
[0042] FIGS. 5a-5d show different exemplary embodiments for the
flexing surface of the sheath surface of the recess;
[0043] FIG. 6 shows a schematic diagram as a top view with a
segmented recess;
[0044] FIG. 6a shows a section B-B from FIG. 6;
[0045] FIG. 7 shows a top view with slit-shaped extensions of the
recess;
[0046] FIG. 7a shows a section C-C from FIG. 7;
[0047] FIG. 7b shows a cross-section view of alternative
embodiments;
[0048] FIG. 8 shows a cross-section view of the perspective view;
and
[0049] FIG. 9 shows a cross-section view of a further
embodiment.
DETAILED DESCRIPTION OF THE INVENTION
[0050] A polishing head 1 according to FIG. 1 comprises a basic
body 2 which is formed of synthetic material with a supporting part
3 which is formed on it made of foam and a polishing foam 4 which
is arranged on the supporting part 3. The basic body 2 serves to
retain a polishing spindle 7 which is not shown further, and
comprises for the purpose of machine handling a collar 2.1 and
catch springs 2.2 for clipping onto the spindle, not shown, or onto
a spindle head.
[0051] The polishing film 4 comprises on its upper side a hole 4.1
which is arranged coaxially to a rotational axis D. Additionally,
further holes 4.4 to 4.4''' are provided at a radial distance.
Furthermore, four recesses 4.7 to 4.7''' are provided on the upper
side, which are not, however, a through-hole.
[0052] It can be seen in FIG. 2 that both the centric hole 4.1 and
the further holes 4.4 to 4.4''' which are positioned further
outwards are formed as a whole, i.e. they extend through the entire
film.
[0053] The polishing film 4 is formed from the two layers 4a, 4b.
The aforementioned holes 4.1-4.4 here pass through both layers 41,
4b. Furthermore, the lower layer 4b comprises a recess or groove
4.5, starting from the respective hole 4.4, which extends through
into the area of the respective recess 4.7.
[0054] The supporting part 3 comprises a centrically arranged
recess 3.1 which extends down to the supporting part 3, starting
from the upper side. The recess 3.1 comprises a cone-shaped sheath
surface 3.2, which comprises an angle .alpha. with the rotational
axis D. The recess 3.1 serves as a polishing agent reserve supply
which is inserted into the recess 3.1 prior to the polishing
process. The respective hole 4.4 to 4.4''' or the start of the
respective groove 4.5 is here provided in the area of an edge 3.3
of the recess 3.1. Were the polishing head 1 to be rotated, the
polishing agent located in the recess 3.1 would be transported
outwards, and consequently upwards, and enters the hole 4.4 or
exits upwards from the hole 4.4 in the area of the edge 3.3. On the
other hand, the polishing agent is transported to the recess 4.7
through the groove 4.5 or the channel which is formed together with
the groove 4.5 and the supporting part 3 and also exits through the
recess 4.7.
[0055] According to the illustration in FIG. 3, the respective
groove 4.5 extends in the radial direction to the recess 4.7,
starting from the hole 4.4.
[0056] As can be seen in FIG. 2, the polishing film protrudes over
the edge 3.3 of the recess 3.1 by an overhang 4.8. The overhang 4.8
is approximately 40% of the half diameter d2 of the recess 3.1.
Accordingly, the polishing agent which is forced upwards or
outwards by the rotation can only exit upwards or radially outwards
through the hole 4.4 or the groove 4.5.
[0057] The groove 4.5 comprises a length 1, wherein the hole 4.4
comprises a distance a from the centric hole 4.1, as a result of
which the overhang 4.8 would at least partially be accounted for.
The recess 4.7 is accordingly distanced from the hole 4.4 by the
length 1 of the groove 4.5, and is at a corresponding distance d
from the hole 4.1.
[0058] Opposite the further hole 4.4, another embodiment of the
further hole 4.4a is shown. The further hole 4.4a is groove-shaped
and is connected to the central hole 4.1. The distance a in this
case relates to the limitation line of the respective hole 4.1,
4.4a which lies radially outside. The size of the respective hole
4.1, 4.4a, as well as the width and length and the number of
further holes 4.4, 4.4a which are distributed around the
circumference can differ depending on the type of application.
[0059] According to the cross-section view A-A from FIG. 3, the
recess 3.1 comprises in the area of the edge 3.3 a diameter d2, and
tapers downwards by approximately 70% to a diameter d3.
[0060] According to the illustration in FIG. 4, the polishing head
1 thus formed can be placed against a surface 8.1 of a workpiece 8
or a lens 8.
[0061] Each of the two layers 4a, 4b of the polishing head 4 are
assigned a separate function area F1, F2. The lower layer 4b
guarantees on the one hand the lid function by means of the
overhang 4.8 over the edge 3.3 of the recess 3.1. Furthermore, the
lower layer 4b fulfils the outlet and onward transportation
function of the polishing agent into the hole 4.4 or into the
groove 4.5 towards the recess 4.7. The upper layer 4a is
essentially assigned the outlet function, since there, the
polishing agent exits from the hole 4.4 or from the recess 4.7 at a
required site and can be incorporated between the polishing film 4
and the surface 8.1 to be machined, and there fulfils the polishing
function or effectively supports it.
[0062] The recess 3.1 can comprise different forms with regard to
its wall surface 3.2 according to exemplary embodiments 5a to 5d. A
limitation line B of the projection of the wall surface 3.2 which
results according to the cross-section view can be funnel shaped
according to FIG. 5a, bow-shaped or parabolic according to the
exemplary embodiments in FIGS. 5b and 5c and/or cylindrical
according to FIG. 5d. In the first three cases, the positioning
angle .alpha. of the wall surface 3.2 varies depending on a height
or depth t of the recess 3.1. This can be advantageous, in
particular in the case shown in FIG. 5c, since in the areas close
to the rotational axis D in the base of the recess, the centrifugal
forces which ac in the radial direction will be smaller than in the
areas which are at a greater distance from the rotational axis,
i.e. in the area of the edge 3.3.
[0063] Even with a cylindrical recess according to FIG. 5d, a
raising of the filling level of the polishing fluid on the edge 3.3
of the recess 3.1 is achieved, so that the polishing fluid can also
exit through the hole 4.4 or the groove 4.5. The height of the
section of the wall surface 3.2 which is raised in relation to the
rotational axis D can, as in the exemplary embodiment shown in FIG.
5a, be greater than the overall depth t of the recess 3.1.
[0064] According to the exemplary embodiment in FIG. 6 and the
associated cross-section view B-B in FIG. 6a, it is provided that
the recess 3.1 is segmented in the circumferential direction U at
least partially, i.e. the recess 3.1 is supplemented by three
wing-shaped extensions 3.1a, 3.1b, 3.1c. Within the wing-shaped
extensions 3.1a, 3.1b, 3.1c, the wall surface 3.2 is raised in
relation to the rotational axis D. The central section of the
recess 3.1 is, insofar as it is limited, cylindrical. The
wing-shaped extensions 3.1a, 3.1b, 3.1c are also three further
segments of the recess 3.1 alongside the central section of the
recess 3.1. Depending on the length and width of the extensions
3.1a-3.1c, the support function of the supporting part is
impaired.
[0065] In the exemplary embodiment shown in FIG. 7, the recess 3.1
is segmented in a similar manner to the exemplary embodiment shown
in FIG. 6, wherein the segmentation is formed by three slit-shaped
extensions 3.1a, 3.1b, 3.1c in the top view which run in the radial
direction. In addition to the central recess 3.1 and the three
slit-shaped extensions 3.1a to 3.1c, an opening 3.7b of a channel
3.7 which is shown in FIG. 7a is shown on the upper side or front
side 3.4 of the supporting part 3.
[0066] According to the cross-section view C-C in FIG. 7a, on the
left-hand side, the slit-shaped extensions 3.1a to 3.1c have the
same depth t as the recess 3.1 itself. The slit-shaped recesses
3.1a to 3.1c are according to the exemplary embodiment in FIG. 7
rectangular with reference to the top view. However, these can also
comprise the ovular, long holes, square or triangular form of a
star point.
[0067] According to the exemplary embodiment shown in FIG. 7a, on
the right-hand side, a channel 3.7 is provided in the supporting
part 3 which, beginning in the central recess 3.1, runs radially
outwards and upwards towards the free front side 3.4. The channel
3.7 comprises a central axis M which with the rotational axis D
comprises an angle .beta. of approximately 55.degree..
[0068] The channel 3.7 forms an opening 3.7a in the wall surface
3.2 of the recess 3.1, which in relation to the central axis M is
placed at a depth t2, measured from the front side 3.4. The channel
3.7 opens out into an opening 3.7b on the front side 3.4. The
opening 3.7b is at a radial distance from the central recess 3.1,
as is shown in FIG. 7.
[0069] According to the exemplary embodiment shown in FIG. 7b, on
the left-hand side, the groove 3.5, can be flatter or less deep
than the central recess 3.1. The groove 3.5 or the groove base 3.6
here has the depth t1 which totals approximately 40 percent of the
depth t of the central recess 3.1.
[0070] According to the exemplary embodiment shown in FIG. 7b, on
the right-hand side, the channel 3.7 can be curved or parabolic, in
a similar manner to the recess according to FIG. 5b or 5c. The
positioning angle .beta. between the central channel axis M and the
rotational axis D thus varies with the radius.
[0071] In general, it is also possible for the groove base 3.6 to
be curved or parabolic according to the exemplary embodiment shown
in FIG. 7b on the left-hand side, in a similar manner to the
channel 3.7 according to the exemplary embodiment shown in FIG. 7b
on the right-hand side. As soon as the depth t1 in the area of the
central recess 3.1 reaches the depth t of the central recess 3.1,
when the groove base 3.6 is curved or parabolic, an embodiment
results which is similar to FIG. 6 or FIG. 6a, according to which a
segmented recess 3.1 with the wing-shaped extensions 3.1a to 3.1c
according to the top view is provided. In contrast to the exemplary
embodiment shown in FIG. 6, the extensions 3.1a to 3.1c are
significantly longer and narrower, and are to this extent more
slit-shaped, than in the exemplary embodiment shown in FIG. 6.
[0072] In the cross-section view shown in FIG. 8, the respective
groove 3.5, 3.5'' is provided in the supporting part. The groove
3.5 extends in the radial direction, starting from the recess 3.1
or its upper edge 3.3, through to the height of the respective hole
4.7, 4.7'' in the polishing film 4. The polishing agent located in
the recess 3.1 is transported out of the cone-shaped recess when a
rotation occurs, and through to the hole 4.7 of the polishing film
4 via the groove 3.5, and finally exits from the hole 4.7. At the
latest when the groove 3.5 is filled with polishing agent,
polishing agent exits the hole 4.4 which is arranged in front of
the hole in relation to the radial direction.
[0073] According to FIG. 8 on the left-hand side, the hole 4.4 or
4.4'' is not provided. Only the hole 4.7'' at the end of the groove
3.5'' is provided from which the polishing agent can exit
outwards.
[0074] The basic body 2 comprises a polishing agent channel 2.3
which is designed as a hole, and which is arranged coaxially to the
rotational axis D. Via the polishing agent channel 2.3, the
polishing head 1 or the recess 3.1 is supplied with polishing agent
as an alternative or a supplement, which is provided by means of a
polishing spindle 7 shown as a sketch in FIG. 4.
[0075] According to the exemplary embodiment shown in FIG. 9, the
recess 3.1 opens downwards to the base part 2 not shown (see FIG.
8). The polishing agent is transported via the respective channel
3.7, 3.7'' to the front side 3.4 of the supporting part. The form
of the recess 3.1 which extends downwards guarantees the
transportation of the polishing agent from the recess 3.1 into the
respective channel 3.7, 3.7'' or its respective opening 3.7a,
3.7a''.
LIST OF REFERENCE NUMERALS
[0076] 1 Polishing head [0077] 2 Basic body [0078] 2.1 Flange,
collar [0079] 2.2 Catch spring [0080] 2.3 Polishing agent channel,
hole [0081] 3 Supporting part [0082] 3.1 Recess, mould [0083] 3.1a
Extension, propeller-shaped, slit-shaped, partial segment [0084]
3.1b Extension, propeller-shaped, slit-shaped, partial segment
[0085] 3.1c Extension, propeller-shaped, slit-shaped, partial
segment [0086] 3.2 Wall surface, sheath surface [0087] 3.3 Edge
[0088] 3.4 Front side, free [0089] 3.5 Groove [0090] 3.6 Groove
base [0091] 3.7 Channel [0092] 3.7a Opening, below [0093] 3.7b
Opening, above, front side [0094] 4 Polishing film [0095] 4a Upper
part, layer [0096] 4b Lower part, layer [0097] 4.1 Hole [0098] 4.2
Inner side [0099] 4.3 Outer side [0100] 4.4 Hole [0101] 4.4' Hole
[0102] 4.4'' Hole [0103] 4.4''' Hole [0104] 4.4a Hole [0105] 4.5
Groove [0106] 4.6 Groove base [0107] 4.7 Recess, hole [0108] 4.7'
Recess [0109] 4.7'' Recess [0110] 4.7''' Recess [0111] 4.8 Overhang
[0112] 7 Polishing spindle [0113] 8 Lens, workpiece [0114] 8.1
Optical spectacle surfaces, aspherical surface [0115] .alpha. Angle
[0116] .beta. Angle [0117] a Distance [0118] b Distance [0119] B
Limitation line [0120] D Rotational axis [0121] d Distance [0122]
d1 Diameter [0123] d2 Diameter [0124] d3 Diameter [0125] F1
Function area [0126] F2 Function area [0127] l Length [0128] M
Central axis channel 3.7 [0129] t Depth [0130] t1 Depth [0131] t2
Depth [0132] U Circumferential direction
* * * * *