Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-11-15
2001-12-25
Hofsass, Jeffery (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S679000, C340S686100, C340S686600
Reexamination Certificate
active
06333696
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a collision preventing device for a measuring apparatus and a measuring apparatus having a collision preventing unit. More particularly, the present invention relates to a collision preventing device for a measuring apparatus and a measuring apparatus having a collision preventing unit, the measuring apparatus measuring dimensions and the like of a work while relatively moving the work and a non-contact probe by a driving system.
2. Description of the Related Art
As a measuring apparatus using a non-contact probe, a non-contact view measuring CMM (Coordinate Measuring Machine) is known. The non-contact view measuring CMM is capable of measuring the dimensions and the like of a work on the basis of an image fetched by a non-contact probe while moving the work or the non-contact probe in an X-axis direction, a Y-axis direction, and a Z-axis direction that are mutually perpendicular to each other.
In
FIG. 13
, a non-contact view measuring CMM
1
is provided with a measuring table
11
and a bridge-type frame
12
. The bridge-type is capable of moving on the measuring table
11
in the Y-axis direction. A guide rail
13
is attached to one side of the measuring table
11
, and one leg
121
of the bridge-type frame
12
moves while sliding in the Y-axis direction along this guide rail
13
.
Here, the relative displacement of the bridge-type frame
12
and the guide rail
13
is measured by a displacement detecting unit including a scale
14
disposed on the guide rail
13
and a detector (not shown) disposed on the leg
121
. It should be noted that an air bearing or the like is provided on the underside of the other leg
122
of the bridge-type frame
12
, whereby the leg
122
is slidably supported on the measuring table
11
.
Meanwhile, an X-axis slider
15
is disposed on a bridge
123
in such a manner as to be slidable in the X-axis direction, and the relative displacement of the bridge
123
and the X-axis slider
15
is measured by a displacement detecting unit similar to that for the Y-axis direction. The bridge
123
bridges between the legs
121
and
122
of the bridge-type frame
12
. Further, a Z-axis supporting member
16
is disposed on the X-axis slider
15
, and this Z-axis supporting member
16
is provided with a Z-axis spindle
17
which is slidable in the Z-axial direction. A non-contact probe
18
is attached to the Z-axis spindle
17
, and this non-contact probe
18
includes a CCD camera
181
and an objective
182
attached to the CCD camera
181
.
The non-contact probe
18
is movable in the X-, Y-, and Z-axis directions by a driving system (not shown) provided in the non-contact view measuring CMM
1
. Although not shown, the driving system has an X-axis driving system, a Y-axis driving system, and a Z-axis driving system for moving the non-contact probe to in the X-, Y-, and Z-axis directions. For example, the driving system is adapted to be operated manually or by inputting coordinates to a computer (not shown) connected to the driving system.
The measurement, the non-contact probe
18
is first moved in the X-, Y-, and Z-axis directions along the work by the driving system. Next, in a state in which the non-contact probe
18
is positioned at a desired position, an image of the work is fetched by the CCD camera
181
. The dimensions and the like of the work are then determined from this image.
The non-contact probe
18
of the above-described non-contact view measuring CMM
1
is used at a position proximate to the work. At the time of measurement, in particular, the non-contact probe
18
is moved in a three-dimensional direction, but there are cases where the non-contact probe
18
is made to collide against the work due to the carelessness of an operator or such as an error in the input setting of coordinates to the computer. In addition, in the case of an apparatus having a number of devices, such as a combination measuring apparatus, a mechanism is often adopted in which the devices are stored except when necessary, and a device, when necessary, is moved to a normal position so as to be used. In such a case as well, unless the distance between the device and the work is proper, there is a possibility of causing the device to collide against the work.
Since the above-described non-contact probe
18
, the devices, and the line are not provided with the collision detecting capability in themselves, even if the non-contact probe
18
, for instance, collides against the work, the driving force of the driving system continues to be applied to the non-contact probe
18
. The driving system stops only when an overload has been applied to the driving system, or an overcurrent has occurred, or an error signal such as a servo tracking error in the driving system has been issued from the driving system. For this reason, there is a problem in that large damage may be possibly imparted to the main body, the driving system, and the non-contact probe
18
of the non-contact view measuring CMM
1
or the work.
SUMMARY OF THE INVENTION
The object of the invention is to provide a collision preventing device for a measuring apparatus and a measuring apparatus having a collision preventing unit which make it possible to prevent the breakage of the non-contact probe, the main body of the measuring apparatus, the work, and the like due to collision.
To attain the above object, the collision preventing device for a measuring apparatus and a measuring apparatus having a collision preventing unit in accordance with the invention has the following arrangements.
The collision preventing device for a measuring apparatus, according to the present invention, measures dimensions and the like of a work while relatively moving the work and a non-contact probe by a driving system and comprises:
a holder attached to the non-contact probe;
an collision detecting portion covering the non-contact probe;
holding means for holding the collision detecting portion displaceably with respect to the holder; and
a switch for detecting a relative displacement between the holder and the collision detecting portion and for commanding the driving system to stop the relative movement of the work and the non-contact probe or relatively move the work and the non-contact probe in a escape direction in which the work and the non-contact probe separate from each other.
According to this invention, when, for example, the non-contact probe has approached the work, the collision detecting portion covering the non-contact probe firstly collides against the work. Then, a relative displacement occurs between the collision detecting portion and the holder. When the relative displacement has occurred between them, the switch immediately detects the relative displacement, and commands the driving system of the measuring apparatus to stop the relative movement or relatively move the work and the non-contact probe in the escape direction. As a result, the movement of the non-contact probe or the work is stopped, or the work and the non-contact probe are relatively moved in the escape direction.
Accordingly, when the non-contact probe is about to collide against the work, since the collision detecting portion covering the non-contact probe is firstly brought into contact with the work, it is possible to prevent the non-contact probe itself to collide against the work, thereby making it possible to prevent the breakage of the non-contact probe and the main body of the measuring apparatus. In addition, since the collision between the collision detecting portion and the work is immediately detected, and the movement of the non-contact probe or the work is stopped, or the work and the non-contact probe are relatively moved in the escape direction, it is possible to prevent damage or the like from being caused to the work. In particular, if the collision detecting portion is formed of a light or soft material such as a plastic or rubber, it is possible to reliably prevent damage or the like from being caused to the work. This col
Arai Masanori
Matsumiya Sadayuki
Hofsass Jeffery
Mitutoyo Corporation
Oliff & Berridg,e PLC
Tang Son
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