GB2152209A

GB2152209A - Apparatus for compilation of measurement data from scaled drawings

Info

Publication number: GB2152209A
Application number: GB08334427A
Authority: GB
Inventors: High Kirk Ramsay
Original assignee: PRACTICAL TECHNOLOGY Ltd
Current assignee: PRACTICAL TECHNOLOGY Ltd
Priority date: 1983-12-23
Filing date: 1983-12-23
Publication date: 1985-07-31
Also published as: GB8334427D0

Abstract

The measuring apparatus comprises a measurement device 2 movable over the scaled drawings and including a transducer 4 and a distance measured sensor preferably in the form of a wheel 5 running on the drawing and actuating the transducer 4 which can be in the form of an optical encoder. The device 2 is coupled to signal processing equipment 3 by a flexible lead 6 which equipment 3 produces and presents a suitable read-out signal. The processing equipment preferably comprises (a) a signal conditioner 8 converting a sine wave signal from the transducer to a square wave, b an up-down digital counter 11 receiving the square wave signal, and (c) a transmitter/receiver 10 passing a measured value signal to a read-out device or preferably a computer 7. The arrangement is such that information can be fed back from the computer 7 to the processing equipment 3 to enable involved multi-part measuring operations to be carried out. A synchronising device 12 is provided for the elements of the apparatus, and the measuring apparatus enables convenient and efficient measuring operations from the scaled drawing. <IMAGE>

Description

SPECIFICATION Measuring apparatus The present invention relates to measuring apparatus enabling direct measurement, especially but not exclusively linear measurements, of dimensions in scaled or working drawings.

The normal procedure for taking dimensions from a scaled drawing has of course involved the use of a rule possibly utilised in conjunction with a pair of dividers. This can be a somewhat cumbersome operation particularly when additionally, the measured values have to be noted down, as required for example when preparing a material specification for a particular job.

It is an object of the present invention to provide improved measuring apparatus enabling dimensions to be conveniently taken from scaled drawings, and to be recorded where desired.

According to the present invention there is provided measuring apparatus for taking measurements from scaled drawings comprising transducer means producing a primary measured signal, a measuring element operatively coupled to said transducer means and movable for the creation of said primary measured signal, and processing means receiving said primary measured signal and producing a read-out vaIuetherefrnm.

Preferably the measuring element operates in conjunction with a marker implement.

Preferably the measuring apparatus is adapted for measuring in both positive and negative senses, and is also able to indicate the specific measured sense.

Preferably the transducer means includes an optical encoder. The measuring element preferably comprised a contact wheel.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings wherein: Figure 1 shows a schematic diagram of measuring apparatus for taking measurements in scaled drawings, in accordance with the present invention; and Figure 2 shows a side elevation of the transducer and measuring device of the apparatus of Fig. 1.

Referring to the drawings, measuring apparatus 1 for directly measuring dimensions in scaled drawings, and especially linear dimensions, essentially comprises a measurement device 2 having included therewith a counter/marker device (not shown), and processing equipment 3 for processing basic measurement signals issued by the measurement device 2 so as to provide a read-out measurement value.

The measurement device 2 basically includes a transducer 4 actuated by a contact wheel 5 which runs on the drawing paper surface in the path of the dimension to be measured. Fig. 2 indicates the measurement path P-P. The data (measurement signals) from the transducer 4 are passed by connecting lead 6 to the processing equipment 3, housed separate from, but adjacent to a computer apparatus including a computer console (shown schematically as 7), and the data connection to the computer apparatus (7) can be achieved using serial data transmission but transmission methods through a parallel port are possible.

Referring specifically to Fig. 1, the transducer 4 comprises an optical encoder actuated by contact wheel 5, and the data issued to the lead 6 from the transducer 4 consists of a sine wave measurement value signal (of magnitude determined by the motion of the wheel 5) and a signal indicating the operational status of the apparatus i.e. whether inactive, active or measuring. The measurement value signal is fed to a signal conditioner 8 within the processing equipment 3 while the status signal is fed directly by lead 9 to a transmitter/receiver device 10 to enable effective start-up of the measuring operation.

The conditioner 8 converts the measured sine wave input signal to a digital square wave output and also produces a signal indicating the direction sense (+ or -) of rotation of the wheel 5, (i.e. an up/down signal).

The digital square wave output is passed to an up/down counter device 11 which counts the square wave to produce a binary coded decimal output which is generally indicative of the measured dimension (the device 11 can be adapted to count up to 999 999 digits).

The counter device 11 will count down if the measurement direction is reversed (i.e. - ve).

The output from the counter device 11 is passed to the transmitter/receiver device 10 which is adapted not only to pass the count information of device 11 to the computer apparatus (7) but also to receive information from the computer: as can be seen in Fig. 1, the transmitter/receiver device 10 can transmit information back to the up/down counter device 11. Thus a single measurement can be completed in discrete stages with intermediate data from the computer (7) being fed back to the counter device 11 to be combined or added to the measured data passing via the conditioner device 8. End of measurement can be indicated by a keyboard entry at the computer console 7. A 'clock' 1 2 is operatively coupled to the transmitter/receiver device 10 to enable synchronisation of the various steps of the measurement process.

Initiation of measurement is achieved by a positive action on the part of the operator by means of a start/stop button 1 3 on the measurement device 2. Also, the device 2 includes an indicator (LED) 14 indicating the status of the device 2, i.e. inactive, active or measuring. The marker device can consist of a pressure sensing pen connected to the same interface unit as the measurement device 2, and can pass data back to the computer apparatus (7) over the same date bank.

Whereas a simple unit counting facility together with a pen marker can be incorporated within the measurement device 2 it would be possible to use a separately located single function unit counter/marker.

Electric power for the measuring apparatus 1 can be taken from a mains supply via a supply lead 1 6 to a power supply console 1 5 within equipment 3.

The above measuring apparatus according to the present invention enables convenient and efficient compilation of measurement data from scaled drawings, but also enables involved multi-part measuring operations to be carried out utilising data feed back from a host computer, and additionally multi-stage measuring techniques can be practiced. It is expected that a precision of greater than 5% will be achievable by the apparatus for each individual measurement operation.

Claims

1. Measuring apparatus for taking measurements from scaled drawings comprising transducer means producing a primary measured signal, a measuring element operatively coupled to said transducer means and movable for the creation of said primary measured signal, and processing means receiving said primary measured signal and producing a read-out value therefrom.

2. Apparatus as claimed in claim 1, wherein the measuring element operates in conjunction with a marker implement.

3. Measuring apparatus as claimed in claim 1 or 2 and adapted for measuring in both positive and negative senses, and which is also able to indicate the specific measured sense.

4. Apparatus as claimed in any one of the preceding claims, wherein the transducer means includes an optical encoder.

5. Apparatus as claimed in any one of the preceding claims, wherein the measuring element comprises a contact wheel.

6. Apparatus as claimed in any one of the preceding claims, wherein the processing means comprises a signal conditioner, and a computer device receiving conditioned signals from the signal conditioner.

7. Apparatus as claimed in claim 6, wherein the signal conditioner converts a sine wave input from the transducer means into a square wave output for delivery to said counter device, the signal conditioner additionally producing a subsidiary indicating signal indicating whether the square wave output has a positive or a negative sense, the counter device being adapted to count up or down.

8. Apparatus as claimed in claim 6 or 7, wherein the counter device forwards a count signal to transmitting and receiving means, said transmitting and receiving means being adapted for coupling to read-out means of the measured value or to computer means.

9. Apparatus as claimed in claim 8, wherein means are provided to enable information to be fed back from said transmitting and receiving means to said counter device.

10. Apparatus as claimed in claim 8 or 9, wherein conduit means directly feed a status signal from the transducer means to the transmitting and receiving means.

11. Apparatus as claimed in any one of the preceding claims, wherein synchronising means are provided to synchronise operation of the various elements of the transducer means and the processing means.

12. Measuring apparatus substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.