GB640339A - Instrument for finding the centre of a circular hole and for providing a basis or datum for measurements or positions in relation to such centre - Google Patents
Instrument for finding the centre of a circular hole and for providing a basis or datum for measurements or positions in relation to such centreInfo
- Publication number
- GB640339A GB640339A GB1739748A GB1739748A GB640339A GB 640339 A GB640339 A GB 640339A GB 1739748 A GB1739748 A GB 1739748A GB 1739748 A GB1739748 A GB 1739748A GB 640339 A GB640339 A GB 640339A
- Authority
- GB
- United Kingdom
- Prior art keywords
- centre
- hole
- datum
- instrument
- bridge arm
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25D—PERCUSSIVE TOOLS
- B25D5/00—Centre punches
- B25D5/02—Automatic centre punches
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Length-Measuring Instruments Using Mechanical Means (AREA)
Abstract
640,339. Tools for setting out work. DRURY, K. G. June 29, 1948, No. 17397. [Class 61(ii)] [Also in Group XX] An instrument for finding the centre of a circular or part circular hole or other datum in relation to such centre comprises a bridge arm 1, adjustable in length, one end 5 of which is adapted to contact with one side of the hole whilst the other end passes at right angles from the centre of a chordal member 2, a slide 6 mounted on the bridge arm 1 and a second arm 7 slidably mounted on the slide with its axis intersecting the axis of the bridge arm and extending at right angles from the centre of a second chordal member 8. When the instrument is adjusted so that each chordal member makes contact with the circular hole, the centre of the hole lies at the intersection of the axes of the arms 1 and 7. The bridge arm is adjusted in length by means of the screw 4. The chordal members 2, 8 are provided with cylindrical rollers 3 by means of which contact with a cylindrical hole is established to ensure that the plane of the instrument is at right angles to the axis of the hole. As shown, the point of intersection of the two axes at the centre of the hole is indicated by a pin 10 and a datum plate 11, rotatable about 'the axis of the centre pin over a dial plate 9 and having faces 12 passing radially from the centre pin for use with a height gauge may be provided. In a modification the centre pin indicator is carried on a block provided with datum faces and adjustably mounted radially of the dial plate by means of a vernier screw. The centre of the circular hole may be located by means of a hole situated at the centre of the datum plate and ground to size for use with mandrils and similar instruments.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1739748A GB640339A (en) | 1948-06-29 | 1948-06-29 | Instrument for finding the centre of a circular hole and for providing a basis or datum for measurements or positions in relation to such centre |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1739748A GB640339A (en) | 1948-06-29 | 1948-06-29 | Instrument for finding the centre of a circular hole and for providing a basis or datum for measurements or positions in relation to such centre |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB640339A true GB640339A (en) | 1950-07-19 |
Family
ID=10094475
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1739748A Expired GB640339A (en) | 1948-06-29 | 1948-06-29 | Instrument for finding the centre of a circular hole and for providing a basis or datum for measurements or positions in relation to such centre |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB640339A (en) |
-
1948
- 1948-06-29 GB GB1739748A patent/GB640339A/en not_active Expired
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