US3396472A

US3396472A - Device to measure diameter and thread pitch of a screw

Info

Publication number: US3396472A
Application number: US561285A
Authority: US
Inventors: Moss Wilfred
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-06-28
Filing date: 1966-06-28
Publication date: 1968-08-13
Anticipated expiration: 1985-08-13

Description

W. MOSS Aug. 13, 1968 DEVICE TO MEASURE DIAMETER AND THREAD PITCH OF A SCREW Filed June 28, 1966 2 Sheets-Sheet l Aug. 13, 1968 w. MOSS 3,396,472

DEVICE TO MEASURE DIAMETER AND THREAD PITCH OF A SCREW Filed June 28, 1966 2 Sheets-Sheet 2 United States Patent 3,396,472 DEVICE T0 MEASURE DIAMETER AND THREAD PITCH OF A SCREW Wilfred Moss, P.O. Box 255, South Duxbury, Mass. 02374 Filed June 28, 1966, Ser. No. 561,285 9 Claims. (Cl. 33-199 This invention relates to a device that measures diameter and thread pitch of a screw, bolt or the like.

One object of my invention is to provide a device that simultaneously gives a reading of the diameter and thread pitch (number of threads per inch) of a screw-threaded member by the simple movement of placing the latter member in an opening in my device and rotating a threaded disc into contact with its threads.

Another object is to provide my device with an indicating arm and disc operably coordinated so that movement of the disc moves the arm to thereby simultaneously obtain two readings, namely, diameter and thread pitch or number of threads per inch.

A further object is to provide such a device formed of parts that are inexpensive to manufacture and simple to assemble that provide an operative device.

The foregoing and other objects which will appear as the nature of the invention is better understood, may be accomplished by a construction, combination and operative arrangement of parts such as in disclosed by the drawing. The nature of the invention is such as to render it susceptible to various changes and modifications, and therefore, I am not to be limited to the construction disclosed by the drawing, nor to the particular parts described in the specification; but am entitled to all such changes therefrom as fall within the scope of my claims.

In the drawing:

FIG. 1 is a front elevational view of my device.

FIG. 2 is a top plan view of my device.

FIG. 3 is an enlarged plan view of the disc used in my device.

FIG. 4 is an enlarged, sectional view taken on the line 4-4 of FIG. 1.

FIG. 5 is an enlarged, fragmentary view on an exaggerated scale of a portion of said disc.

As illustrated, I provide supporting means having a front plate 12 which has a cut-out 14 at the right side to provide visibility as later explained. This plate 12 has a pivot hole 16 and adjacent the left side thereof is a slot 18 that extends vertically as shown in said FIG. 1. A rectangular cut-out 20 in said means 10 is provided at the lower left side intermediate the top and bottom, the lower border line of which provides a guide or rest 22 to receive a screw-threaded member S to be measured as later explained.

Said supporting means has a back plate 26 that is spaced from said front plate 12 slightly by spacers 27, and it has indicia 28 thereon at the right side to indicate the diameters of different screw-threaded male members S as later explained. Said back plate 26 has a pivot hole 30 that aligns with said hole 16 and a slot 32 similar to and that aligns with said slot 18 when said supporting

plates

12 and 26 are assembled.

A disc gauge 36 extends from one side extremity of said supporting means and into said opening 20, and it has a hole 38 in the center and at the periphery there are threads 42 in different portions thereof and of different sizes that correspond with the different sizes of the threads of a threaded member S to be gauged or measured. Said disc gauge 36 is shown on its face as a polygon divided into triangular portions or sectors 44, each of which extends from the center thereof to a straight line at the periphery. Said screw-threaded member S makes interfitting contact with said threads 42 of one of the triangular portions 44 when being measured to determine its thread pitch and diameter.

To determine diameter of said member S I provide an indicator arm 50 having a pointed portion 52 at one end which extends laterally to a point adjacent said back plate indicia 28. Said arm has a hole 54 therethrough opposite said

holes

30 and 16 and a pivot pin or rivet 56 passes through said

holes

16, 54 and 30 so that some rotation of said arm is permitted. Another hole 58 in said arm 51 aligns with said slot 18,

holes

38 and 58 and slot 32. A pin or rivet 60 thereby rotatably connects said disc 36 to said arm and both said

plates

12 and 26.

In operation, a screw-threaded member S is placed in the opening 20, resting on said guide or rest 22 bordering said rectangular opening. Said disc 36 along with said arm 50 are drawn downwardly in said

slots

18 and 32 until said disc is close to or slightly contacts said member S. Then said disc is rotated until the threads 42 that mesh or interfit the threads of member S are reached. Then the indicia 46 directly opposite or above said member S is noted which gives the thread pitch or number of threads per inch. Simultaneously the indicia 28 at the far right, that said arm pointed portion 52 is now opposite, gives the diameter of said member S.

For instance, in said FIG. 1, the periphery of the disc sector portion marked with the indicia 18P, being opposite said member S, and the threads interfitting, the thread pitch is 18. The vertical or linear movement of the disc 36 also moved said arm 50 and at the termination of this disc movement the pointed portion 52 is opposite the numeral 7 on said back plate indicia 28. This gives the reading of the diameter as 1 as well as that of the thread pitch.

The distance from the center 38 of said disc 36 to the outside point or crest 58 of a plurality of disc threads may be the same when my device is used to obtain thread pitch and diameter of a relatively small range of sizes of coarse threaded members S such as 13F to 18F, for instance. This is so because the position of said indicator arm 50 is only slightly affected by very small differences in thread pitch and will give an accurate reading of diameter even though the pointed portion 52 does vary its position slightly.

When the thread pitch range reaches to relatively high numbers, as occurs in fine threaded members, the distance from said disc center 38 to the outer crest 58 of the disc threads must vary in accordance with the different sizes of threads. In a 13 pitch thread, for instance, the distance may measure 1.000 inch, while in a 48 pitch thread the distance may rneasure .963 inch as illustrated in said FIG. 5. But the distance from said disc center 38 to the root or inner crest 60 should be constant in the various sizes as shown in said FIG. 5. This variation is necessary to compensate for substantial differences in thread depth in different sizes of threaded members since the coarser threads are deeper than the finer ones as illustrated in said FIG. 5. By compensating for this difference at the periphery of said disc 36 the diameter reading obtained will be accurate whereas it would be inaccurate otherwise.

Thus whether the threads of a member S are 13 pitch or 48 pitch, upon rotation of the disc to the point where the threads thereon interfit with those of said member 3, the diameter reading will be the same because of said compensation.

What I claim is:

1. A device to determine diameter and thread pitch of a screw-threaded member comprising supporting means having an opening intermediate the top and bottom thereof and having a slot therethrough, a disc extending into said opening having a plurality of straight edges. at

the periphery thereof extending angularly to each other, and threads formed in said edges, an indicating arm, first means rotatably connecting said arm and said supporting means, second means extending through said slot, arm and disc rotatably connecting said disc to said arm and to said supporting means, said second means being slidable in said slot whereby said disc may be moved about said first means, said a-rm extending from and beyond said disc.

2. A device as set forth in claim 1, the threads in one said edge varying in pitch from those in another.

3. A device as set forth in claim 1, said supporting means having indicia thereon indicating different diameters of a said member, said arm extending to a point adjacent said indicia.

4. A device as set forth in claim 1, said supporting means having a front plate and a back plate spaced therefrom, said disc and arm extending between said plates.

5. A device as set forth in claim 4, said back plate having indicia marked thereon adjacent a side extremity thereof, said front plate having a cut-out at a side extrernity thereof so positioned as to make said indicia visible.

6. A device as set forth in claim 4, said disc extending laterally beyond said supporting means.

7. A device as set forth in claim 1, the face surface of said disc having marking lines thereon dividing said surface into triangular portions from the center of said disc to the periphery thereof, each said triangular portion having said threads at the periphery thereof, the pitch of 4 threads of one said triangular portion varying from that of another said triangular portion, each said triangular portion having indicia thereon within its marking lines indicating threads per inch corresponding to the thread pitch at its periphery.

8. A device as set forth in claim 2, the distance from the center of said disc to the outer crests of said threads varying between one said edge and another, the coarser threads lextending farther outwardly than the finer threads.

9. A device as set forth in claim 8, the distance from the center of said disc to the inner crests of said threads being substantially the same.

References Cited UNITED STATES PATENTS 1,465,920 8/1923 Francis 33-168 2,027,217 1/1936 Zerkle 33-199 2,210,560 8/1940 Allen et a1. 33199 2,664,638 1/1954- Storey 33-168 2,901,829 9/1959 Lucas 33--168 2,933,817 4/1960 Puckett et a1. 33-168 OTHER REFERENCES Tool & Die Journal, June 1949, p. 130, A New Model Gear Gage (copy in group 283).

LEONARD FORMAN, Primary Examiner.

JOEL M. FREED, Assistant Examiner.

Claims

1. A DEVICE TO DETERMINE DIAMETER AND THREAD PITCH OF A SCREW-THREADED MEMBER COMPRISING SUPPORTING MEANS HAVING AN OPENING INTERMEDIATE THE TOP AND BOTTOM THEREOF AND HAVING A SLOT THERETHROUGH, A DISC EXTENDING INTO SAID OPENING HAVING A PLURALITY OF STRAIGHT EDGES AT THE PERIPHERY THEREOF EXTENDING ANGULARLY TO EACH OTHER, AND THREADS FORMED IN SAID EDGES, AN INDICATING ARM, FIRST MEANS ROTATABLY CONNECTING SAID ARM AND SAID SUPPORTING MEANS, SECOND MEANS EXTENDING THROUGH SAID SLOT, ARM AND DISC ROTATABLY CONNECTING SAID DISC TO SAID ARM AND TO SAID SUPPORTING MEANS, SAID SECOND MEANS BEING SLIDABLE IN SAID SLOT WHEREBY SAID DISC MAY BE MOVED ABOUT SAID FIRST MEANS, SAID ARM EXTENDING FROM AND BEYOND SAID DISC.