Geometrical instruments – Distance measuring – Scale reading position sensor
Reexamination Certificate
1999-01-20
2001-01-30
Fulton, Christopher W. (Department: 2859)
Geometrical instruments
Distance measuring
Scale reading position sensor
C033S702000, C033S707000
Reexamination Certificate
active
06178656
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to scales and more particularly to a device and method for mechanically adjusting graduation-scale carrier members.
RELATED TECHNOLOGY
A device and a method for mechanically adjusting graduation-scale carrier members are disclosed in German Patent No. 27 27 769 C2 for a joint (side-by-side surfaces) between two side-by-side mounted graduation-scale carrier members. The patent describes assembling a scale standard of a linear measuring device from individual graduation-scale carrier members. Graduations, which supply incremental positional data during an optical scanning operation, are arranged on the individual graduation-scale carrier members. A scale construction of this kind is selected in particular when the scale that is needed is no longer able to be manufactured in one piece due to the substantial measuring length required of the measuring system. However, a problem encountered when working with a scale assembled from a plurality of graduation-scale carrier members is that when the gap separation at the joints of adjacent graduation carriers is not optimally adjusted, errors occur when positional determinations are made. For this reason, the aforementioned patent proposes making an adjustment to adjacent graduation-scale carrier members at the joints. The suitable adjustment elements include pressing means to permit the graduation-scale carrier member to be assembled with an interference fit, but nevertheless in an adjustable manner in the joint area.
What is disadvantageous in the context of this patent is that the device is relatively expensive. Another drawback is that it can only be used at joints between graduation-scale carrier members. Furthermore, considerable space is required for the adjustment elements.
A length or angle measuring instrument and a related method for making linear adjustments are disclosed in European Patent Application No. 150 354 A2. In this context, the measuring graduation-scale carrier member can be expanded or compressed to adjust the carrier member linearly. The device includes a graduation-scale carrier member that is perforated in the measuring direction. Torque is exerted on gear wheels, forcing them into engagement with these perforations. In response to the acting torque, the sections between two gear wheels are expanded or compressed in length until the desired linear adjustment is reached, and the gear wheels are subsequently fixed in position.
Here, the drawback is that this device is not able to adjust the gap width at joints of adjacent graduation-scale carrier members. A further disadvantage is the costly construction and the substantial space requirements it entails.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method and a device for mechanically adjusting graduation-scale carrier members, which can be used both for performing linear adjustments in the area of a graduation-scale carrier member, as well as to adjust the gap width at the joints between two graduation-scale carrier members. A further object is to be able to adjust disk-shaped graduation-scale carrier members. The device preferably has a small space requirement and renders possible a simple, as well as precise, adjustment.
The present invention provides a device for mechanically adjusting graduation-scale carrier members and joints between graduation-scale carrier members, which form the scale of a preferably incremental linear or angle measuring instrument, by changing the effective length of the graduation-scale carrier members or of the gap width at the joint. In the graduation-scale carrier member (
2
,
10
,
20
), cut-outs are provided. Adjusting devices mesh with the cutouts. Provision is made in the graduation-scale carrier member (
2
,
10
,
20
) for wedge shaped segments (
11
a
,
11
b
,
21
a
,
21
b
,
21
c
). Adjusting elements (
6
a
-
6
h
,
7
a
,
7
b
,
7
a
1
,
7
a
1
,
7
b
1
,
7
b
2
,
12
a
,
12
b
,
13
a
,
13
b
,
22
,
23
a
,
23
b
,
31
,
32
) surround the wedge-shaped segments (
11
a
,
11
b
,
21
a
,
21
b
,
21
c
) with at least partial form-locking.
The present invention also provides a method for mechanically adjusting graduation-scale carrier members and joints (
1
) between graduation-scale carrier members, which form the scale of a preferably incremental linear or angle measuring instrument, by changing the effective length of the graduation-scale carrier members or of the gap width at the joint. In the graduation-scale carrier member (
2
,
10
,
20
), cut-outs are provided into which adjusting devices mesh. When an adjustment is made to setting screws (
6
a
-
6
f
,
13
a
,
13
b
,
23
a
,
23
b
,
32
), different starting torques are exerted; this force exerted orthogonally to the measuring direction using the setting screws (
6
a
-
6
f
,
13
a
,
13
b
,
23
a
,
23
b
,
32
) onto the fixing elements (
7
a
,
7
b
,
12
a
,
12
b
,
22
,
31
) is converted by the wedge-shaped form locking connections between the fixing elements (
7
a
,
7
b
,
12
a
,
12
b
,
22
,
31
) and the segments (
11
a
,
11
b
,
21
a
,
21
b
,
21
c
) of the graduation-scale carrier members (
2
,
3
,
10
,
20
) into a force on the graduation-scale carriers (
2
,
3
,
10
,
20
), which has a component that is parallel and orthogonal to the measuring direction (x), enabling the graduation-scale carrier members (
2
,
3
) to be fixed orthogonally to the measuring direction (x) and shifted in parallel to the measuring direction (x).
Further advantageous features of the device may include: (a) that the adjusting elements (
6
a
-
6
h
,
7
a
,
7
b
,
12
a
,
12
b
,
13
a
,
13
b
,
22
,
23
a
,
23
b
,
31
,
32
) include fixing elements (
7
a
,
7
b
,
7
a
1
,
7
a
2
,
7
b
1
,
7
b
2
,
12
a
,
12
b
,
22
,
31
), which have a wedge-shaped Cut-out or a wedge-shaped protuberance, and include setting screws (
6
a
-
6
h
,
13
a
,
13
b
.
23
a
,
23
b
,
32
); (b) that the wedge-shaped cut-outs at the fixing elements (
7
a
,
7
b
,
12
a
,
12
b
,
22
) are designed to be slightly smaller than the wedge-shaped segments (
11
a
,
11
b
,
21
a
,
21
b
,
21
c
) of the graduation-scale carrier member (
2
,
10
,
20
); and/or (c) that provision is made in the area of one joint (
1
) of two graduation-scale carrier members (
2
,
3
) for wedge-shaped segments on both graduation-scale carrier members (
2
,
3
), and each fixing element (
7
a
,
7
b
) has two wedge-shaped cut-outs, which each enter into a form-locking connection with segments of different graduation-scale carrier members (
2
,
3
).
In accordance with the present invention, adjustment elements having wedge-shaped cut-outs cooperate with wedge-shaped segments on the graduation-scale carrier members. The wedge-shaped cut-outs of the adjustment elements are pressed with an adjustable pressure onto the wedge-shaped segments of the graduation-scale carrier members. The wedge-shaped form of the adjustment elements and of the segments produces a force component, which acts in the longitudinal extension direction of the graduation. This enables a graduation-scale carrier member or a joint between two graduation-scale carrier members to be adjusted by varying the pressure used to press the adjustment elements onto the graduation-scale carrier members.
Performing a linear adjustment to adjacent graduation-scale carrier members in accordance with the method and device of the present invention is also easily done. For this, wedge-shaped segments, capable of being adjusted by a common adjusting element, are provided on both adjacent ends of the graduation-scale carrier members.
Furthermore, the device and the method of the present invention are also suited for performing an adjustment on round graduation-scale carrier members, as used in angle measuring instruments.
The device or the method of the present invention can be used directly at the location, i.e., the individual graduation-scale carrier members that constitute a scale can be assembled and precisely adjusted in one sequence of operation. Moreover, the de
Dr. Johannes Heidenhain GmbH
Francis Faye
Fulton Christopher W.
Kenyon & Kenyon
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