Geometrical instruments – Gauge – Circular size
Reexamination Certificate
1999-03-30
2001-12-18
Gutierrez, Diego (Department: 2859)
Geometrical instruments
Gauge
Circular size
C033S550000, C033S552000, C033S557000
Reexamination Certificate
active
06330753
ABSTRACT:
TECHNICAL DOMAIN
This invention relates to a measuring apparatus and method that bears the characteristics of employing mechanical method to measure large-diameter-workpiece; especially using with compact measuring apparatus, in the field of measuring technology.
BACKGROUND OF THE TECHNOLOGY
The characteristic of measuring large diameters is that the measuring apparatus is usually with large dimension and heavy weight, which leads to many problems such as much difficulty of operation in situ, complexity of calibration, large deformation and high cost. The roller way (Page 21-22, Volume 1, Foreign Metrology, 1991) provided a method to measure large diameters with compact measuring apparatus. It is necessary to include many parts in such method, such as the roller, badge, sensor of revolution, sensor of compaction, disk of glass grating, pulse counter, microprocessor, keyboard, digital-displaying device and so on. The diameter of the workpiece is obtained by counting the revolution of the known-diameter roller that is contacted with and rotated purely following the workpiece, when the workpiece rotates a whole or several whole numbers of revolution. The method suffers the following disadvantages. (1) Since the slippage of the roller on the surface of the workpiece is inevitable, it usually suffer the problem of bad repeatability and limited accuracy, which is the vital disadvantage of this method. (2) The measuring apparatus is complex and expensive. (3) Because the workpiece must revolve while measuring, it can only be employed on machine. (4) The workpiece to be measured must has a whole circumference.
CONTENTS OF THE INVENTION
The purpose of this invention is to provide a large diameter gauge that has the features of simple structure, small volume, high accuracy and good versatility. After marking down the parameters of the measuring units tightly placed around the workpiece and getting the closed size by measurement, an equation with the diameter to be measured as the variable can be obtained according to the geometric relations. Then, the diameter of the workpiece can be solved from this equation.
In order to achieve above purpose, a series of independent measuring gauges (measuring units) and some accessories were arranged according to this invention. Each measuring gauge consists of two positioning elements, a fastener and a body. The two positioning elements are a ball and a roller, which are placed at the two ends of the body. The fastener is placed on the body. Its action is to position the measuring gauge around the circumference of the workpiece through the two positioning elements and fix it. The fastener should ensure that the measuring gauge does not off-contacts with the workpiece owing to the gravity of the measuring gauge at any position.
The subject matter of the invention is described as follows: It consists of a series of independent measuring gauges and some accessories. Each measuring gauge consists of two positioning elements, a fastener and a body. The two positioning elements are a ball and a roller respectively, which are placed at the two ends of the body. The fastener is set on the body. The diameters of the ball and roller, which are above-mentioned two positioning elements, are known. They may not, but suggested, be equal. The distance between the axis of the roller and the center of the ball (hereinafter referred to as the Central Distance) is also known. The central distance of every gauge may not, but suggested, be equal. If the roller is looked upon as the head and the ball as the end, the measuring gauges are placed and, with fastener, around the circumference of the cylinder or hole to be measured in such a way that each adjacent gauges are contacted head to end or end to head. The gauges are arranged in such a way that the contacting elements between the adjacent gauges are one ball and one roller, so that the contacting area of every two adjacent gauges is always a point, reducing the contact error and improving the measurement precision. In addition, the operation is easier. Do in such way until the remnant space between the first and the last gauge is not large enough to be put into another one gauge. Now measure the closed size, i.e., the distance between the roller's axis of the first gauge and the ball's center of the last gauge, or that between the ball's center of the first gauge and the roller's axis of the last gauge. If the diameters of all the balls and rollers are equal and the central distance of all the gauges are equal, the following equation can be obtained according to the geometrical relations of the gauges and workpiece.
n2
α
+
(
n
-
1
)
2
β
+
2
γ
=
2
π
where
sin
α
=
l
D
±
d
sin
β
=
d
D
±
d
sin
γ
=
l
′
D
±
d
where D is the diameter to be measured, d is the diameter of the ball or roller, l is the central distance,
1
′ is the closed size and n is the number of the gauges that surround the workpiece. The sign “+” in the sign “+” of the above equation means the situation that the outside diameter is measured and “−” means the situation that the inside diameter is measured. Then, the following equation can be obtained.
n
sin
-
1
l
D
±
d
+
(
n
-
1
)
sin
-
1
d
D
±
d
+
sin
-
1
l
′
D
±
d
=
π
The diameter D can be solved from the above equation with computers or the programmable calculators. If the diameters of the rollers and balls and the central distances of the gauges are not equal each other, the diameter of the workpiece can be also obtained in the similar way according to the geometrical relations of the gauges and workpiece, in which the actual values of those parameters of the gauges are employed.
The above-mentioned way of measuring large diameters is named the circling way, in which the measuring gauges are placed and fixed sequentially and head to end or end to head around the circumference of the cylinder or hole to be measured with the fasteners. Put the gauges one by one until the space between the first and the last gauges is not large enough to be put into another one gauge. Now we can mark down the parameters of the gauges placed and measure the closed size. Then the diameter of the workpiece can be obtained through the geometric relations.
The invention is with the following characteristics:
1. Versatility: Both external and internal diameters of cylinder or hole can be measured, and there is no upper limitation of measuring range. Even if there is a gap or more in the cylinder or hole, the diameter can also be measured.
2. Simple structure, compact volume and easy to be operated. Even one person can accomplish the whole measurement.
3. Easy to be calibrated. Because the central distance of the gauges and the diameters of the roller and the ball are small, the measuring gauges are easy to be calibrated accurately with the available precision instruments.
4. Low cost.
5. High precision. Because the central distance of the gauges and the diameters of the roller and the ball can be calibrated accurately, and the measurement is performed on the whole circumference of the workpiece, the method has very high precision.
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patent: 2831256 (1958-04-01), Werle
patent: 3311986 (1967-04-01), Zawistowski
patent: 4324049 (1982-04-01), Blose
patent: 4586266 (1986-05-01), Leumann
patent: 4729174 (1988-03-01), Caron et al.
patent: 4765065 (1988-08-01), Bennett
patent: 4976045 (1990-12-01), Schley
patent: 5732475 (1998-03-01), Sacks et al.
patent: 5778553 (1998-07-01), Hollensbe
patent: 1270668 (1972-04-01), None
patent: 2197477 (1988-05-01), None
patent: 03296613 (1991-12-01), None
patent: 0226180 (1968-09-01), None
Arent Fox Kintner & Plotkin & Kahn, PLLC
De Jesus Lydia M.
Gutierrez Diego
Southeast University
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