US3340616A

US3340616A - Micrometer

Info

Publication number: US3340616A
Application number: US455428A
Authority: US
Inventors: Mincuzzi Antonio
Original assignee: Borletti SpA
Current assignee: Fratelli Borletti SpA; Borletti SpA
Priority date: 1964-05-13
Filing date: 1965-05-13
Publication date: 1967-09-12
Anticipated expiration: 1984-09-12
Also published as: GB1081775A; CH410446A

Description

sept 12 1967 A. MlNcuzzx 3,340,616

f' 4 5a 27 T/g-VQ 25 B y *JMJ A Horne ys Sept. 12, 1967 A. MlNcuzzl 3,340,616

MIGROMETER Filed May 13, 1965 2 Sheets-Sheet 2 Attorneys United States Patent O 3,340,616 MICROMETER Antonio Mincuzzi, Milan, Italy, assignor to Soc. per

Azioni Fratelli Borletti, Milan, Italy, an Italian company Filed May 13, 1965, Ser. No. 455,428 Claims priority, application Italy, May 13, 1964, 10,444/ 64, Patent 47,148 7 Claims. (Cl. 33-166) The manufacture of micrometers, particularly those of the -Palmer type, various arrangements have hitherto been adopted for enabling the scale to be read quickly and with high accuracy. For this purpose, there have in particular been proposed micrometers having counting mechanisms.

The control of the counting mechanism, the position of which on the micrometer is determined solely by reasons of design, is effected via a gear train driven by the rotary member that controls the micrometric screw of the calibrating rod.

In one construction of more practical interest the counting mechanism, which is generally constituted by a series of flanged rings carrying the number on their outer surfaces, is located coaxially with the Calibrating rod, which therefore passes through the said rings.

A construction of this type, which is of particular interest in view of its simplicity as regards construction, operation and adjustment, is provided in accordance with the present invention. This construction comprises the feature that the Calibrating rod, an extension of which is provided with the micrometric screwthread, is capable of rot-ating relative to a nut xed to the body of the micrometer, by means of a universal joint controlled by a rotatable sleeve. The importance of the said universal joint, the operation of which will be described hereinafter, is

particularly noticeable in large scale or mass production,

where it is possible that during assembly the axis of rotation of the calibarting rod and the axis of rotation of the control sleeve may not come perfectly into coincidence. In this case the universal joint nevertheless permits perfect transmission of motion from the control sleeve to the calibrating rod.

The following description with reference to the accompanying drawings, which illustrate a preferred embodiment of the invention, discloses the main features and the advantage of such a micrometer.

In the drawings:

FIG. 1 is an external view of a micrometer according to the invention in which can be seen the counting mechanism, the circumferential micrometric graduation and the locking lever,

FIG. 2 is a longitudinal section, on a larger scale than FIG. 1, of the control assembly for the Calibrating rod,

FIG. 3 is a cross section on the line III-III of FIG. 2,

FIGS. 4 and 5 show a detail of the sliding joint connecting the sleeve and the Calibrating rod, and

FIG. 6 shows a detail of two shells of plastic material that cover the handle of the micrometer.

The body 1 of the micrometer, which has a handle 2 of arcuate form, includes a cylindrical hollow body portion 3 which is located in line with an anvil 4 and in which is housed the counting mechanism 5.

A member 7 is rigidly fixed by means of a screwthread 6, to the portion 3 so as to form a single piece therewith. The member 7 is extended at 8 by a sleeve which is screwthreaded at 9. On the screwthread are Screwed two

nuts

10, 10 which serve respectively as nut and locking nut which provide locating nut means. Between the nut 10 and the shoulder 11 of the member 7 is accurately located a bushing 12 which is capable of turning on the outer surface 13 of the extension 8 without being able to move 3,340,616 Patented Sept. 12, 1967 ICC axially. The bushing 12'is in turn rigidly xed in the nterior of a control sleeve 14 by means of screws 15, hence the sleeve 14 can rotate freely relative to the member 7, being guided by the bushing 12, without being able to slide axially.

In the inner part of the end of the sleeve 14 remote from the bushing 12 is inserted an inner sleeve 18, this being releasably locked against a shoulder 16 by means of an end cap 17. The sleeve 18 has longitudinal inwardly opening groove 19 the centres of which are on a diametrical plane.

In the two diametrically opposed grooves 19 can slide the ends 20 of two pins 21 with plane parallel faces, lixed in diametrically opposite positions to a collar 22. The latter is mounted, so as to be capable of slight oscillation, on the end 23 of the Calibrating rod 24 within the sleeve 14, by means of a locating pin 25 the axis of which is normal to the common axis of both said pins 2,1.

The assembly constituted by the collar 22, pins 21, and pin 25 forms a universal joint which can turn slightly about the pin 25 and can also undergo slight displacements in the direction of the arrow 26. l

When the sleeve 14 is caused to rotate the universal joint above mentioned also rotates, and this causes the calibrating rod 24 to rotate with it. The rod 24 has an extension 27 with a micrometric screwthread which engages with the internal screwthread 28 in the extension 8, and which causes the Calibrating rod 24 to move along its axis, for example in the direction of the arrow 29. Displacement in the opposite sense would clearly be elfected by turning the sleeve 14 in the opposite direction. The Calibrating rod is thus mounted by screwthread 2'8 and by an internal cylindrical bore of member 7, for rotation and laxial sliding movement in and relative to the hollow body.

The end of the extension 8 is slotted at 30 along a diametrical plane, and externally is of sli-ghtly conical shape and is screwthreaded. A nut 31 is screwed onto this screwthread to the extent that some play is left between the internal screwthread 28 and the screwthreaded shank of the Calibrating rod.

Rotation of the sleeve 14 is transmitted by means of an internally toothed wheel 32 to a wheel 33, ya shaft 34, a wheel 35, a wheel 36 (see FIG. 3) and nally to a wheel 37 fixed to a disc 40 actuating'the counting mechanism comprising an assembly of numbered rings through a tooth 41.

For setting to zero the micrometer the end of the calibrating rod 24 is brought against the anvil 4; then the cap 17 is unscrewed so that the inner sleeve 18 will be freely rotatable in the respect of the sleeve 14, and the sleeve 14 is rotated so that all numbered rings of the counting mechanism 5 Will be brought to zero, the Calibrating rod being maintained fixed.

The cap 17 is now locked again and the phasing of the sleeve 14 in the respect of the counting mechanism 5 is performed through the ring 38 having a graduation 46. To this aim the ring 38 will be rotated on the sleeve 14 in the respect of the index 47 ixed to the body 1 and locked in the zero position through screw dowels 39. The screwthreads on the end cap 17 thus constitute one means for xedly securing the cap on sleeve 14 in a position to bear against sleeve 18 and lock sleeve 1-8 against movement relative to sleeve 14.

In a preferred construction the transmission ratio between the successive numbered

rings

43, 44 and 45 is such that the iirst ring makes one rotation for two tenths of a millimetre of movement of the Calibrating rod, the second ring for two millimetres, the third for twenty millimetres and the fourth for two hundred millimetres. The latter however can turn only through two iigures, the extent of measurement of the micrometer being -25 mm.

The ratios and the values indicated by the numbered rings may obviously be different from those -above mentioned, and in particular the scale may be in inches instead of millimetres, without exceeding the scope of the invention.

Accuracy of reading is obtained by observing the graduation 46 on the ring 3S relative to an index mark 47 xed to the body.

The counting mechanism is mounted in the interior of the cylindrical zone 3 after being assembled on the ringcarrier 48 which is adapted to be inserted in the cavity in the Zone 3 of the body. The carrier 48, which carries both the numbered rings and the yassociated pinions is locked in this cavity by the end cover 50 which is screwed into position at 51, via a spring 52 and an interposed sleeve 48 which also serves to protect the numbers.

The counting mechanism is actuated by means ot one or the other of two rings 53 which draw the sleeve 14 into rotation by friction. Each ring 53 has slip friction connection with control sleeve 14 to limit the torque that can be applied to sleeve 14 by a ring 53. This sleeve in turn operates via the grooves 19 and the pins 21 to effect rotation of the calibrating rod 27-24 which, screwing at 2S, is caused to move axially until it engages the object to be measured, the object being placed between the anvil 4 and the end of the calibrating rod 24. The pressure with which the calibr-ating rod engages the object to be measured depends on the value of the couple that the friction of the two rings 53 is able to transmit to the sleeve 14. This pressure or measuring load is preferably of the order of 1 kg.

By means of a handle 54 mounted for rotation on the xed hollow body with an eccentric pin 54 a pin 55 can be shifted axially to lock the relatively rotatable bushing 12 by pressure on its surface, thus enabling the relevant reading to be made without error.

The handle 2 is protected by two

shells

56 and 57, preferably made from plastic material, which are forced onto the curved part of the body, causing at least one projection 58 on one shell to enter a corresponding recess in the opposing shell.

What I claim is:

1. A counter micrometer comprising a hollow body, a calibrating rod, means mounting the calibrating rod for rotation and axial sliding movement in and relative to the hollow body, a control sleeve mounted for rotation on the hollow body, counting mechanism disposed in the hollow body and adapted to be actuated by rotation of said control sleeve, means defining on the inner side of said control sleeve an inwardly opening groove that extends longitudinally of the control sleeve, a member extending into said groove and slidable longitudinally of said groove, and means interconnecting said member Iand said calibrating rod for conjoint rotation and for swinging movement of said calibrating rod and said member relative to each other.

2. A counter micrometer as claimed in claim 1, said means dening said groove comprising an inner sleeve disposed within said control sleeve, said inner sleeve having two diametrically opposed said longitudinal grooves, and said member having two diametrically opposite projecting pins engaging in said grooves.

3. A counter micrometer as claimed in claim 1, said means dening said groove comprising an inner sleeve mounted in said control sleeve for rotation of said inner sleeve and said control sleeve relative to each other about the axis of said sleeves, and means for releasably securing said inner sleeve in fixed position relative to said control sleeve thereby accurately to set the micrometer,

4. A counter micrometer as claimed in claim 3, said releasably securing means comprising an end cap removable to expose said inner sleeve, and means for xedly securing said cap on said control sleeve in a position to bear against said inner sleeve and lock said inner sleeve against movement relative to said control sleeve.

5. A counter micrometer comprising a hollow body, a calibrating rod, means mounting the calibrating rod for rotation and axial sliding movement in and relative to the hollow body, a control sleeve mounted for rotation on the hollow body, counting mechanism disposed in the hollow body and adapted to be actuated by rotation of said control sleeve, a ring mounted for rotation on and relative to said control sleeve, said ring having graduations thereon registrable with a xed mark on said hollow body, means for selectively locking said ring on said control sleeve thereby accurately to set the micrometer, a bushing disposed within and fixed to the control sleeve, and locating nut means screw-threadedly carried by said hollow body, said bushing being disposed between said nut means and an annular shoulder on said body and serving to guide the rotation of the control sleeve without play.

6. A counter micrometer comprising a hollow body, a calibrating rod, means mounting the calibrating rod for rotation and axial sliding movement in and relative to the hollow body, a control sleeve mounted for rotation on the hollow body, counting mechanism disposed in the hollow body and adapted to be actuated by rotation of said control sleeve, a ring mounted for rotation on and relative to said control sleeve, said ring having graduations thereon registrable with a -iixed mar-k on said hollow body, means for selectively locking said ring on said control sleeve thereby accurately to set the micrometer, and a handle on said hollow body, a pair of shells of plastic material disposed on opposite sides of said handle, and a projection on one said shell extending into a recess in the other said shell thereby to hold the shells together on opposite sides of the handle.

7. A counter micrometer comprising a hollow body, a calibrating rod, means mounting the calibrating rod for rotation and axial sliding movement in and relative to the hollow body, a control sleeve mounted for rotation on the hollow body, counting mechanism disposed in the hollow body and adapted to be actuated by rotation of said control sleeve, la. ring mounted for rotation on and relative to said control sleeve, said ring having graduations thereon registrable With a lixed mark on said hollow body, means for selectively locking said ring on said control sleeve thereby accurately to set the micrometer, and locking means comprising an eccentric member mounted for rotation on the hollow body and having means adapted to engage between a xed part and a rotatable part of the micrometer thereby to tix said parts releasably together to enable a correct reading to be made.

References Cited UNITED STATES PATENTS 756,461 4/1904 Borduas 33-166 1,107,202 `8/1914 Savage 33-116 1,638,366 8/1927 Sandoz 33-164 1,389,028 8/ 1931 Colburn 33-166 2,957,248 10/1960 Stedman et al 33-164 3,120,061 2/ 1964 Pfleiderer 33-166 FOREIGN PATENTS 467,023 11/ 1951 Italy.

LEONARD FORMAN, Primary Examiner.

WILLIAM D. MARTIN, Examiner.

Claims

1. A COUNTER MICROMETER COMPRISING A HOLLOW BODY, A CALIBRATING ROD, MEANS MOUNTING THE CALIBRATING ROD FOR ROTATION AND AXIAL SLIDING MOVEMENT IN AND RELATIVE TO THE HOLLOW BODY, A CONTROL SLEEVE MOUNTED FOR ROTATION ON THE HOLLOW BODY, COUNTING MECHANISM DISPOSED IN THE HOLLOW BODY AND ADAPTED TO BE ACTUATED BY ROTATION OF SAID CONTROL SLEEVE, MEANS DEFINING ON THE INNER SIDE OF SAID CONTROL SLEEVE AN INWARDLY OPENING GROOVE THAT EXTENDS LONGITUDINALLY OF THE CONTROL SLEEVE, A MEMBER EXTENDING INTO SAID GROOVE AND SLIDABLE LONGITUDINALLY OF SAID GROOVE, AND MEANS INTERCONNECTING SAID MEMBER AND SAID CALIBRATING ROD FOR CONJOINT ROTATION AND FOR SWINGING MOVEMENT OF SAID CALIBRATING ROD AND SAID MEMBER RELATIVE TO EACH OTHER.