GB2066471A

GB2066471A - Digital height gauge

Info

Publication number: GB2066471A
Application number: GB8033895A
Authority: GB
Original assignee: Mitutoyo Manufacturing Co Ltd
Current assignee: Mitutoyo Manufacturing Co Ltd
Priority date: 1979-10-23
Filing date: 1980-10-21
Publication date: 1981-07-08
Also published as: GB2066471B; DE3039875A1; JPS5665410U; DE3039875C2

Abstract

A digital height gauge includes a slider (16) mounting a detachable jaw (20) and movable up and down support shafts (12, 14), a transducer in the slider for converting the slider movement into electric signals, and a display device (22) providing a digital display derived from the transducer output, batteries 36 for supplying power to the converter and the display means being stored in the slider in an opposed position relative to the jaw in order and to balance the weight of the carriage. <IMAGE>

Description

SPECIFICATION Digital height gauge The present invention relates to a digital height gauge.

Height gauges have been used in the past in order to measure the height of an object, and such a gauge with a digital display means has recently been proposed in order to provide the advantage of accurate measurement without reading error.

This height gauge has a display means installed in a slider, and the displayed numbers can be easily read during operation. The height gauge however has a drawback in connection with the movement of the slider during the operation of measurement, because the height gauge requires an electric power supply separate from the height gauge itself and a cable electrically connecting the power supply to the slider in order to power a converter in which the movement of the slider is converted into an electric signal, and to power the display means.

Accordingly, the present invention provides a digital height gauge comprising a carriage mounting a jaw and movable up and down along a support, a converter in the carriage arranged to convert movement of the carriage into an electrical signal, and a display device in the carriage for providing a digital display dependent on the electric signal, the electric power for the converter and the display device being derived from at least one battery stored in the carriage.

The carriage can carry a movable or detachable jaw or scriber and be capable of sliding up and down along a pair of spaced support shafts. The weight of the slider carriage can be balanced by suitably positioning the battery or batteries, in particular at the opposite end from the jaw. The carriage can thus be symmetrically balanced with respect to the support or support shafts.

The present invention is further described below by way of example with reference to the accompanying drawings, in which: Figure 1 is a front view of a height gauge with a digital display embodying the invention; Figure 2 is a front view on a larger scale of part of the height gauge, partly in section and with parts away to show the interior of a carriage or slider included in the height gauge; Figure 3 is a sectional view taken on line Ill-Ill of Figure 2; and Figure 4 is a sectional view taken on line lV-IV of Figure 2.

The illustrated digital height gauge of the present invention comprises support shafts 12 and 14 extending upwardly from a base 10, a carriage in the form of a slider 1 6 capable of moving up and down on the shafts 12 and 14, and a jaw or scriber 20 for making contact with an object to be measured. The scriber 20 is detachably connected to a holder 1 8 which is fixed on the slider 1 6. Mounted at the front portion of the slider 1 6 is a digital display device comprising liquid crystal display elements or light emitting diodes, and in the vicinity of the digital display device there are mounted various operational switches.As shown, these operational switches can comprise an on-off switch, an inch and metric unit selection switch 26, a preset switch 28, a zero-set switch 30 and a hold switch 32.

Inside the slider 1 6 there is a transducer or converter which converts the amount of movement of the slider 1 6 into an electrical signal.

In the illustrated gauge the amount of movement of the slider 1 6 is converted into electric signals by a photoelectric converter. Figure 2 shows the internal structure of the slider 1 6 which includes means whereby the relative movement of the slider 1 6 and the support shaft 14 is converted to an angular movement of a slit disc 34, the degree of rotation of which is photoelectrically detected to provide electric signals of a predetermined kind.

In accordance with the present invention, batteries 36 are stored inside the slider 1 6 to supply the necessary electric power to the photoelectric converter co-operating with the slit disc 34, and to the display device 22. The batteries 36 are stored in a position opposed to the jaw or scriber 20. A battery compartment lid 38 is detachably connected to the slider 1 6 by a screw 40 so that the batteries 36 can be easily exchanged.

The structures of the photoelectric converter and the battery compartment are described below with reference to Figures 3 and 4.

Along one side of the supporting shaft 12 are provided rack teeth which mesh with a pinion 44 on a shaft 42 rotatably supported by the slider 1 6.

Rotation of an operating wheel 46 fixed to the shaft 42 causes movement of the slider 16 up and down to a desired height along the support shafts 12 and 14. In a similar way, rack teeth are formed on one side of the support shaft 14 and mesh with pinions 52 and 54 on shafts 48 and 50 provided in connection with the photoelectric converter.

The shafts 48 and 50 are rotatably supported in bearing plates 56 and 58. Between an adjustable bearing 62 screwed into a threaded aperture in a bearing bridge 64 attached to the bearing plate 56, there extends a rotable shaft 66, and gears 70 and 72 on the shafts 48 and 50 mesh with a pinion 68 on this shaft 66. The thrust bearing 64 provides a bias along the axis of the shaft 66 by means of a spring 74, in order to regulate to a correct position the slit disc 34 which is fixed to the shaft 66. This permits an accurate relative movement between the thrust bearing 64 and an index plate 76 fixed to the bearing plate 58.

The gear 72 is fixed on the shaft 50, so that the relative movement of the support shaft 14 and the slider 16 is transferred by rotation of the pinion 54 to the rotating shaft 66. The gear 70 provided on the shaft 48 is however free to tum on the shaft 48 and is coupled to it by means of a spring 78, in order to eliminate backlash in the gears, the revolution of the shaft 48 being transferred to the shaft 66 by the gear 70 by operation of the spring 78 acting between the shaft 48 and the gear 70.

Accordingly, the backlash produced toward the direction of movement of the slider 16 is absorbed by the spring 78 and the extent of movement of the slider 1 6 in either direction is correctly converted into rotational movement of the slit disc 34.

On opposed sides of the slit disc 34 and the index plate 76 are located an emitter 80 and a receiver 82, as illustated in Figure 3, whereby the rotation of the slit disc 34 is detected in terms of electric signals, which are supplied to the display device 22 through circuit elements on a printed circuit base board 84. This detected signals are converted into display signals in a processing circuit composed of LSI provided in the base of the display device 22, which displays the height measured by the gauge in digital terms.

Electric power for the photoelectric converter and the display device 22 is supplied from the batteries 36 stored in the battery compartment 86 provided in the slider 16. Because of this, the height gauge does not require a cable connection to a power supply section, and the height gauge can operate extremely efficiently.

Since the battery compartment 86 can be a die casting or the like provided with holes for receiving batteries, the fastening of the battery compartment lid 38 by the screw 40, after insertion of the batteries 36 can effect reliable storage and electrical connections, and further ensures that the batteries 36 are easily exchanged.

The batteries 36 are stored at the opposite end of the slider 1 6 from the scriber 20. Consequently, the weight of the slider 1 6 can be equally balanced to reliably eliminate measurement errors due to unbalance.

As described above, the present invention provides for batteries to be stored in the slider to eliminate the need for an external electric power supply and a connecting cable, so that movements during the measuring operation can be facilitated with an improvement in efficiency in practical use.

Claims

1. A digital height gauge comprising a carriage mounting a jaw and movable up and down along a support, a converter in the carriage arranged to convert movement of the carriage into an electric signal providing a display device in the carriage for providing a digital display dependent on the electric signal, the electric power for the converter and the display device being derived from at least one battery stored in the carriage.

2. A digital height gauge as claimed in claim 1 wherein the location of the one or more batteries in the carriage is such as to balance the weight of the carriage about the support.

3. A digital height gauge as claimed in claim 1 or 2 wherein the one or more batteries are stored in the carriage at the opposite end thereof from the jaw.

4. A digital height gauge substantially as herein described with reference to the accompanying drawings.