US 3758956 A
Micrometer comprises a spindle which is axially advanced by rotating a knob or ring and a digital indicating counter actuated in response to movement of said spindle and seated in the guide for said spindle. The micrometer comprises means for adjusting the counter and means for taking up any play between the spindle and spindle guide.
Claims available in
Description (OCR text may contain errors)
United States Patent Nakata Sept. 18, 1973 MICROMETER COMPRISING A DIGITAL COUNTER  Inventor: Kiyohiro Nakata, Kure, Japan  Assignee: Yehan Numata, Yokohama City,
Japan  Filed: May 1, 1972  Appl. No.2 249,277
 Foreign Application Priority Data May 11, 1971 Japan 46/3764)  US. Cl. 33/166  Int. Cl. G0lb 3/18  Field of Search 33/166  References Cited UNITED STATES PATENTS 3,120,061 2/1964 Pfleiderer 33/166 3,340,616 9/1967 Mincuzzi 33/166 FOREIGN PATENTS OR APPLICATIONS 20,771 0/1909 Great Britain 33/166 Primary ExaminerHarry N. Haroian AttorneyJoseph F. Brisebois et a1.
 ABSTRACT Micrometer comprises a spindle which is axially advanced by rotating a knob or ring and a digital indicating counter actuated in response to movement of said spindle and seated in the guide for said spindle. The micrometer comprises means for adjusting the counter and means for taking up any play between the spindle and spindle guide.
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MICROMI'ITER COMPRISING A DIGITAL COUNTER SUMMARY OF THE INVENTION This invention relates to a micrometer comprising a digital counter which indicates in large numerals the value measured by the micrometer, which value is also indicated by a scale on the micrometer spindle.
It is an object of the invention to provide such a micrometer in which any longitudinal error caused by thrust during rotation of the spindle is eliminated by suitable take-up means eliminating axial play between the spindle and the main body of the micrometer.
It is a further object of the invention to provide means for adjusting the value indicated by the counter for a given axial position of the spindle.
Other objects of the invention will become apparent from a reading of the following description of a preferred embodiment of the invention, with reference to the accompanying drawings, in which:
FIG. 1 is a side view, partially in axial section, showing one embodiment of the micrometer according to the invention; and
FIG. 2 is a sectional view, taken along the line ll-ll of FIG. 1.
Referring now to FIG. 1, reference numeral 34 indicates a knob fixed to a screw 34A, screwed into the internally threaded part 8A of a hollow spindle 8. The left end of the screw 34A has left-handed threads, so that the.knob and spindle turn as an integral unit. A collar 27 encircles the end of the part 8A of the spindle and is rigidly connected to the part 8A so as to rotate therewith. A eap 29 is gripped between the collar 27 and knob 34.
On the collar 27 are screwed a nut 23 having an inwardly projecting flange 23A and a nut 28 covered by the cap 29.
A plurality of balls 24 are seated in an annular groove in the member 20, which forms part of the main stationary body of the micrometer. The flange 23A engages one side of these balls, while the ring 25, on the other side of these balls is spaced from the collar 27 by the spring 26. It will be appreciated that this arrangement permits the spindle 8 and collar 27 to rotate freely with respect to the body 20, while the action of the spring prevents any relative axial movement therebetween, since the flange 23A and 25 act as jaws gripping the balls to prevent such axial movement.
A knurled ring 41 is held on the nut 23 by a set screw 30, so that the nut 23, collar 27 and spindle 8 may be rotated by the ring 41. The ring 41 comprises a ring gear 22, the internally projecting teeth of which engage a pinion 21 mounted on a shaft 19 journalled in the body part 20. Rotation of the ring 41 thus turns the pinion 21, the shaft 19, and the pinion 18 at the other end of the shaft 19. The pinion l8 drives a gear 16, rotatably mounted on the part 83 of the spindle 8. The gear 16 is integral with member which drives the first wheel 40A of a counter 40. The subsequent wheels 40B, 40C, and 40D of this counter are driven successively in a conventional manner, with each wheel being turned through one-tenth of a revolution each time the preceding wheel completes a full revolution. A window 42, through which the numbers on the wheels may be viewed, is provided in the main body 1 of the micrometer. An auxiliary or vernier scale may be attached to the ring gear 22 and cooperate with an index on the main body.
The left end of the spindle 8 is externally threaded and encircled by a sleeve 6 fixed to the feeler 2. As best seen in FIG. 2, the feeler 2 is provided with a longitudinal external groove which receives the end of a key screw seated in the main body. The arrangement is such that rotation of the spindle 8 causes the feeler 2 to slide axially in the main body, since relative rotation therebetween is prevented by engagement of the tip of the keyscrew 32 in the longitudinal groove in the feeler 2.
Rotation of the spindle is produced by rotation of either the knob 34 or the knurled ring 41, and such rotation results in corresponding rotation of the wheels of the counter, as previously described.
If it becomes necessary to adjust the position of the counter wheels which corresponds to a particular position of the spindle and feeler, the screw 30 is loosened. This permits the nut 23 and ring gear 22 to be rotated about the spindle 8, while driving the counter wheels through the gears 22, 19 and 20, until the desired relative position is attained. The set screw 30 may then be tightened again.
What is claimed is:
1. In a micrometer comprising a main body (20), an elongated feeler (2) axially slidable within said body, elongated rotatable means (34, 8, 23, 27, 28, 29) for axially sliding said feeler with respect to said body, and a counter (40) connected to indicate changes in the position of said feeler relative to said body, the improvement which comprises:
resilient means (26) biassing said rotable means to a constant longitudinal position relative to said main body,
a gear (22) carried by said rotatable means and connected to drive said counter when there is relative movement between said rotatable means and said main body, and
means (30) operable from outside said micrometer to separably fasten said gear to said rotatable means, so that said gear may be unfastened from said rotatable means and actuated to change the indication given by said counter without rotating said rotatable means.
2. A micrometer as claimed in claim 1 comprising ball bearing means (24) seated in said body and jaws (23A, 25) carried by said body and gripping said bearing means, one of said jaws (25) being movable longitudinally of said rotatable means and biassed toward said bearing means by said resilient means.
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