GB2028508A - Digital electronic micrometer - Google Patents

Abstract

A digital electronic micrometer adapted to convert the movement of a spindle (5) into digital signals by an encoder interlocked with the spindle (5), wherein a knob (7) is secured to the frame (1) with adequate spacing from the thimble (6) of the micrometer and a power source (9) is incorporated inside the knob. <IMAGE>

Description

SPECIFICATION Digital electronic micrometer This invention concerns a digital electronic micrometer and, more specifically, it relates to an improvement in a digital electronic micrometer adapted to convert the movement of a spindle into electric digital signals by way of an encoder and display a measured value in a digital manner.

In digital electronic micrometers, an encoder is adapted to interlock a spindle which hoids an object to be measure between it and an anvil, the moving amount of the spindle is converted into digital signals and measured value is displayed, for example, on a liquid crystal display. A small sized satisfactory micrometer capable of direct reading with no reading errors can thus be provided.

Particularly, the detection accuracy obtained by the encoder can be much higher than that of a digital micrometer incorporating a mechanical counter, that is, by a factor of ten or more. Such a digital electronic micrometer requires an electric power source for a digital signal detection device, a counter circuit, an operation circuit, a display device or the like. Conventional digital electronic micrometers having electric cells incorporated in the main body are adapted to buiid-in the power source to the inside of the frame of the micrometer main body. It has thus been necessary in the use of conventional digital electronic micrometers to conduct the measurement by setting the frame on a micrometer stand or the like, holding an object to be measured on one hand and turning the thimble of the micrometer by the other hand.In the use of a digital electronic micrometer, it is, however, considered much more convenient if the micrometer can be constituted so as to hold an object to be measured by one hand and manipulate the thimble as well as hold the frame by the other hand without setting it on a micrometer stand or the like. Realization of an electronic micrometer enabling the measurement with the foregoing simple way of handling is thus highly desired.

Unfortunately, since cells as a power source requiring a large space as well as the digital signal detection device, the counter circuit, the operation circuit and the display device are-contained in the frame of the conventional digital electronic micrometers, the distance between the frame and the thimble is much more increased as compared with usual mechanical micrometers, thus rendering it impossible to manipulate the thimble by the same hand that holds the frame.While an additional knob may be mounted to the main body of the micrometer for facilitating the gripping, it will then lead to a further defect of much difficulty in one-hand manipulation for the thimble since the power source, that is, dry cells incorporated in the frame attaches an excess weight on the side of the anvil to break the baiance in the weight of the entire body.

It is, accordingly, an object of this invention to provide a digital electronic micrometer capable of overcoming the foregoing defect and enabling measurement with ease while keeping the balance of the micrometer in one-hand manipulation, in which a knob is provided extending from the frame close to the thimble so as to enable the manipulation of the thimble with the same hand that grips the knob, and a power source of a great weight, that is, dry cells are incorporated to the inside of the knob.

It is another object of this invention to provide a digital electronic micrometer capable of measurement with ease and at high accuracy even in such a convenient manner as holding an object to be measured by one hand while holding the micrometer as well as manipulating the thimble by the other hand without setting the micrometer on a micrometer stand or the like.

The foregoing objects of this invention can be attained according to this invention by the provision of a digital electronic micrometer adapted to convert the moving amount of the spindle abutting against an object to be measured into digital signals by way of an encoder interlocked thereto and display the measured values in a digital manner, characterized in that a knob is provided to the frame with an adequate gap to the thimble of a micrometer and a power source is incorporated to the inside of the knob.

These and other objects, as well as advantageous features of this invention will be better understood by the following detailed descriptions of this invention in conjunction with accompanying drawings, wherein Figure 1 shows a plan view of a preferred embodiment of a digital electronic micrometer according to this invention with the cover of the knob removed; Figure 2 shows a plan view partially in section of the embodiment as shown in Figure 1; Figure 3 shows and end view along the line Ill-Ill in Figure 2; Figure 4 shows a side view of the embodiment as shown in Figure 1; Figure 5 shows a plan view partially in section of another embodiment of a digital electronic micrometer according to this invention; and Figure 6 shows an end view along the line VI--VI in Figure 5.

Figure 1 through Figure 4 shows a preferred embodiment of a digital electronic micrometer according to this invention and Figure 5 and Figure 6 show another embodiment according to this invention. In each of the embodiments, the digital electronic micrometer has a rigid frame 1 generally in an U shape cast from iron or the like, and one extreme end of the frame 1 is secured with an anvil 2 and the other extreme end of the frame 1 is formed with a spindle support 3 and a casing 4. A spindle 5 coaxial with the anvil 2 is slidablyjournaled axially in the spindle support 4.

A thimble 6 is coaxially engaged to the outer end of the spindle 5 by way of thread means having a predetermined pitch, so that the spindle 5 can be moved optionally closing to or aparting from the anvil 2 by the rotation of the thimble 6 which is fixed regarding the axial direction.

The spindle support 3 incorporates therein an encoder interlocked with the spindle 5 for converting the movement of the spindle into electric pulses. The encoder uses such a device as comprising a disc having a plurality of radial slits and rotating together with the thimble 6, a light emission element (lamp or the like) and a photoreceptive element disposed respectively on opposite sides of the slitted disc, and means for converting the number of intermittent optical shots incident from the light emission element through the slits on the photo-receptive element upon rotation of the thimble 6 into electric pulses in proportion to the number of rotation of the thimble 6, and adapted to detect the moving amount of the spindle in correlation with the number of rotation of the thimble 6 by the number of pulses.The principle and the structure of such encoder are well known and no further reference will be made.

A large scale integrated circuit (LSI) for counting the electric pulses (spindle movement) detected by the encoder and indicating the measured value in a digital form is incorporated in the casing 4. For direct reading, the measured value is displayed in a digital form on a display 4A provided on the cover of the casing.

A knob 7 is secured to the end face of the casing 4 of the frame 1 and it extends as far as the beneath of the thimble 6 with an adequate gap thereto in the direction generally in parallel with the axis of the spindle 5. The gap between the knob 7 and the thimble 6 is determined such that the thimble 6 can be rotated with ease by the same hand that grips the knob 7. The knob 7 is formed as a rigid member and it may either be secured as a separate member to the frame 1 or be cast integrally with the frame 1. Further, the knob 7 may be positioned above or side of the thimble 6, as well as beneath the thimble 6. The knob 7 is formed therein with a space 8 in which dry cells 9 are enhoused for operating the encoder and the LSI.

The dry cells used herein may include conventional ones, for example, disc-shaped silver oxide cells or nickel-cadmium cells connected in appropriate number as shown in Figures 1 to 4, or cylindrical manganese cells or alkaline-manganese cells connected in appropriate number as shown in Figures 5 and 6. The use of mercury cells or lithium cells is also possible.

A switch 10 is attached to the end of the knob 7 for the connection and disconnection of power supply to the circuit from the dry cell 9 incorporated in the frame 1.

In the use of a digital electronic micrometer according to this invention, the switch 10 is put to ON at first and an object to be measured is positioned between the anvil 2 and the spindle 5.

Then, the thimble 6 is rotated to move the spindle 5 toward the anvil 2 and the object is exactly held between the spindle 5 and the anvil 2.

The moving amount of the spindle 5 relative to the reference position where the spindle 5 directly abuts against the anvil 2, that is, the longitudinal zero position is detected as electric pulses generated from the encoder, counted in the LSI and displayed on the display 4A in a digital form.

As foregoing, in each of the digital electronic micrometer according to this invention, since the knob 7 is secured to the frame 1 and extended to a position below the thimble 6 with an adequate gap therefrom in the direction in parallel with the axis of the spindle 5, the turning operation for the thimble 6 can be made with ease by the same hand that grips the knob 7.

Moreover, since the centre of gravity of the micrometer is set closer to the knob 7 by incorporating the cells of a great weight in the knob 7, the micrometer can easily be supported at the knob even by one hand. In other words, use of both hands for the gripping and manipulation as in conventional micrometers is no more necessary.

Accordingly, measuring work can be performed with ease and at high accuracy by holding the micrometer at the knob by the same hand that turns the thimble while holding the object to be measured with the other hand without setting the micrometer on a micrometer stand or the like as usual. This invention can thus make the handling of the micrometer much more convenient.

Claims (5)

1. A digital electronic micrometer adapted to convert the moving amount of a spindle abutting against an object to be measured into digital signals by an encoder interlocked with said spindle and display the measured value in a digital manner, characterized in that a knob is provided secured to the frame with an adequate gap to the thimble of the micrometer and a power source is incoporated inside said knob.

2. A digital electronic micrometer as claimed in claim 1 , wherein the knob is projected from said frame generally in parallel with the axis of said spindle.

3. A digital electronic micrometer as claimed in claim 1 wherein the power source is dry cells.

4. A digital electronic micrometer as claimed in claim 1, wherein the frame is genrally of an U shape whose one extreme end is secured with an anvil and the other extreme end is formed with a spindle support and a casing, said spindle support enhousing the encoder and said casing having means for displaying in digital manner the measured value based on the signals issued from said encoder, and said knob is secured to said casing.

5. A digital electronic micrometer substantially as hereinbefore described with reference to Figures 1 to 4 of Figures 5 and 6 of the accompanying drawings.