CA1099912A - Electronic measuring tape - Google Patents
Electronic measuring tapeInfo
- Publication number
- CA1099912A CA1099912A CA288,755A CA288755A CA1099912A CA 1099912 A CA1099912 A CA 1099912A CA 288755 A CA288755 A CA 288755A CA 1099912 A CA1099912 A CA 1099912A
- Authority
- CA
- Canada
- Prior art keywords
- screen
- measuring tape
- lines
- hook
- housing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B3/00—Measuring instruments characterised by the use of mechanical techniques
- G01B3/10—Measuring tapes
- G01B3/1061—Means for displaying or assisting reading of length measurement
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B3/00—Measuring instruments characterised by the use of mechanical techniques
- G01B3/10—Measuring tapes
- G01B3/1061—Means for displaying or assisting reading of length measurement
- G01B3/1069—Electronic or mechanical display arrangements
Abstract
ABSTRACT
An electronic measuring tape for automatic reading of a measured length. A tape is provided wound on a spool in a housing and when measuring, the tape is pulled off the spool out of the housing. Means are provided both on the tape and within the housing to generate an optical interference pattern when moving the tape relative to the housing. Means are provi-ded for reading the said interference pattern and electronically providing a measurement based on the interference pattern read.
An electronic measuring tape for automatic reading of a measured length. A tape is provided wound on a spool in a housing and when measuring, the tape is pulled off the spool out of the housing. Means are provided both on the tape and within the housing to generate an optical interference pattern when moving the tape relative to the housing. Means are provi-ded for reading the said interference pattern and electronically providing a measurement based on the interference pattern read.
Description
9~2 This invention relates to an electronic measuring tape, which is automatically read optically and where the measured length is shown in a digital manner on a display, Known types o~ ~le~ible measuring tapes are intended for manual visual reading.
Known devices for automatic indication of measurements often are very complicated and cannot be taken along like a usual measurlng tape, but are i]ntended primarily for industrial use.
The present invention relates to a measuring tape, which is intended to be used as a normal measuring tape, for example as the known tape meter, and be taken along by a person, for example a private person for home-use or a craftsman at work, The present invention relates to an electronic measur-ing tape ~or automatic reading a measured length, which tape in non-operative position is stored on a spool in a housing, and for measuring can be pulled out of said housing, comprising a first and a second portion of a transmitter unit, which portions comprise screens consisting of opaq~e lines separated by light : 20 or transparent lines The invention is characterized in that the screen of the first portion is located on the measuring tape, and the screen o~ the second portion is located in said housing immedi-ately closely to the screen of the first portion, whereby an interference pattern, a so-called moir~ pattern, arises upon movement o~ the screen of the first portion relative to the screen of the second portion when viewing the screen o~ the first portion through the screen of the second portion, and that a reading means is provided to optically read said interference pattern.
The invention is described in the following, with re~erence to the accompanying drawing, in which 1~?9~
, Fig, 1 is a lateral view of a tape meter, to which the present invention is applied, Fig. 2 is a view from above of the tape meter, Fig 3 shows a first embodiment o~ the screen o~ the first and second portion, Fig. 4 shows a second embodiment of the screen of the first and second portion, Fig. 5 is an electric wiring diagram for converting light pulses to voltage pulses In Fig 1 a measuring tape in the form o~ a tape meter 10 is shown, which comprises a tape 11 supported in wound-up state in a spool 12 in a housing 13 about an axle 14 For measuring a length, the tape 11 is pulled out of the housing.
The terminating points of the measuring distance preferably consist of a hook 15 attached to the forward edge of the tape 11 and a reference hook 16 stationary on the housing 13, or some other suitable reference hook. Upon pulling the tape 11 out of the housing 13, energy is stored in a spring means (not shown), which in known manner causes the tape be reeled into the housing after completed measuring by action of said spring.
Furthermore, in known manner a pawl is provided, by which the tape 11 can be stopped in partially or fully pulled-out position In Fig. 1 the pawl is illustrated by a control button 17, which is pushed in to release the pawl and pulled out to actuate the pawl.
For certain kinds of measuring a tongue 18 can be folded out in known manner to a position in parallel with the tape 11 on the opposite side of the housing 13, as shown in Fig. 1. When the tongue is folded in, it is fitted into a groove ~not shoY~) in the housing 13 to a position indicated by the dashed line 19 in Fig. 1.
The measuring tongue 18 being in folded-out state, 991~2 measuring takes place between the hook 15 on the tape 11 and the hook 20 at the outer end of the measuring tongue 18 The tape 11 and measuring tongue 18 preferably are made of a steel material as used for usual tape meters The housing 13 preferably is made of a steel material or strong plastic material.
As mentioned above andl shown in Figs l, 2 and 3, the device according to the invention comprises a first portion 21 and a second portion 22 of a transmitter unit, which portions 21, 22 comprise screens The screen 21 of the ~irst portion is located on the upper surface of the tape ll in Fig 1, and the screen 22 of the second portion is stationary located in the housing 13 The screens of the first and second portion consist o~ opaque lines 23 separated by light or transparent lines. For the sa~e o~ clarity, only a ~ew opaque lines 23 are shown in the Figures.
When two screen consist o~ opaque lines separated by transparent interspaces, an interference patter, a so-called moiré pattern, arises when viewing a first screen through a second screen. Depending on the design of the two screens rela-tive to each other, di~ferent types o~ moiré pattern can be caused to arise According to the present inven~ion, the opaque lines 23 associated with the screen 21 o~ the ~irst portion are lo-cated substantially perpendicularly to the longitudinal direc-tion of the tape ll, and the opaque lines 23 associated with the screen 22 o~ the second portion are located substantially in parallel with the opaque lines 23 of the first portion 21 When the tape ll is being pulled out o~ the housing 13 for measuring a distance, and thereby the first screen 21 is moved perpendicularly to the opaque lines 23 on the second screen 22, an inter~erence pattern of migrating wide dark bands 99~l2 24 arises, for example as shown ln Fig 2, when viewing the first screen 21 through the second screen 22 According to the present invention, the screens 21, 22 are designed so that the screen 21 of the first portion has a division, i.e a number o~
opaque lines 23 per length unit perpendicular to the lines 23, which differs ~rom the division of the screen 22 of the second portion.
This difference in division preferably is obtained thereby, that the opaque lines 23 on the two portions 21, 22 have the same width, and that the width o~ the light or transparent lines in the screen 21 of the first portion is dif~erent from the width in the screen 22 of the second portion.
According to a modified embodiment, however, the width of the opaque lines 23 as well as the width of the light or transparent lines in the screen 21 of -the first portion are dif-ferent from the width in the screen 22 of the second portion.
By designing the screens 21, 22 as indicated above, an inter-~erence patterns is obtained which9 as stated, consists of wide dar~ bands 24 when the screen 21 of the tape moves relative to the screen 22 of the second portion.
The migration direction of the wide bands 24 depends on which of the two screens 21, 22 has the densest division.
Fig. 3 shows by way of example an embodiment where the screen 22 of the second portion has a denser division, i e a greater number of opaque lines 23 per length unit perpen-dicular to the l:ines 23, than the screen 21 o~ the ~irst por-tion. As a result thereof, the wide bands 24 migrate in a direction marked by the arrow 25 when the tape 11 is pulled in a direction marked by the arrow 26 When the screen 21, 22 of the first and second por-tion have a different division, the wide bands 24 will migrate through a distance, which is longer than the distance, through 99~2 which the tape 11 has moved. Thereby a ratio is obtained between the distance, through which the tape 11 moves, and the distance, through which the wide bands 24 move Consequently, the movement of the tape 11 can be read with higher accuracy by means of the migration of the wide ban~s 24 than by a reading directly against the tape 11.
The ratio thus obtained depends on the difference in division between the screen 21, Z2 of the first and second portion. In order to obtain a high ratio, i e. a great number of wide bands 2~ passing a point on the second screen 22 for a certaln movement of the tape 11, the difference in division between the screens 21, 22 of the two portions must be small, When, for example, the opaque lines 23 on the two screens 21, 22 have the same width, for example 0,6 mm, and ~he light or transparent lines therebetween have a width on one screen of 0,5 mm and on the second screen o~ 0,3 mm, a ratio of the magnitude of about 10 times is obtained, i.e. the wide bands 24 seem to migrate over the screen 21, 22 a distance 10 times longer than the distance ~hrough which the tape 11 was moved.
In this example, thus, is shown that a substantially higher accuracy with respect to the measuring of the movement of the tape 11 can be obtained by the device according to the inven-tion, compared with direct measuring on the tape 11 as, for example, in the case of a tape meter.
According to a preferred embodiment of the invention, the screen 21 of the first portion consists of opaque lines 23 separated by light, preferably white lines, and the screen 22 of the second portion consists of opaque lines 23 separated by transparent :Lines The second portion preferably is made of a transparent p:lastic material, on which said screen 22 has been applied.
A reading means provided in the housing 10 comprises 9~2 one or more light diodes 27 or the like for lighting the screens 21, 22 of the transmitter unit and one or more photo-transistors 28 or the like for recording the interference pat-tern or patterns According to the preferred embodiment, the light diode 27, or light diodes, and the phototransistor 28, or phototrans~
istors are located on that side of the screen 22 of the second portion which faces away from t~e screen 21 of the first por-tion.
When the screen 21, 22 of the first and second portion, respectively, consists of one screen, one light diode 27 and one phototransistor 28 are used.
At measuring and recording the interference pattern, the light diode 27 lights through the screen 22 of the second portion, whereby the light is reflected against the screen 21 of the first portion and further is transmitted through the screen 22 of the second portion to meet the phototransistor 28 When the tape 11 is being pulled out of the housing 13, thus, a plurality of migrating dark bands 24 will cause the light from the light diode 27 to meet the phototransistor 28 in the form of pulsating light. The phototransistor con-verts these light pulses to electric pulses, which are ampli-fied and processed in an electronic unit suitable for this purpose By arranging the screens 21, 22 of the two portions so that a high ratio of the aforesaid kind is obtained, a great number of electric pulses can be obtained from the phototrans-istor for a relative small movement of the tape 11.
It also appears from the aforesaid, that a high ac-curacy with respect to a distance, through which the ta~e 11is moved, is obtained with the device according to the present invention, without its components having to be designed with 9~
a corresponding high precision In order to obtain a very high accuracy, according to a further embodiment the screen of the first or second por-tion is di~ided into two screens The screen 22, for example, ` of the second portion consists of two screens 22a, 22b with different division, where the parti.tion line 23 between the screens 22a, 22b is perpendicular to the opaque lines 23 and located symmetrically on the second portion, as shown in Fig. 4, One of the two screens 22a, 22b has a division, which is denser than the division of the screen 21 of the first por-tion, and the second one of the two screens 22a, 22b has a division, which is more sparse than the division of the screen 21 of the first portion. When, for example, one screen 22a in Fig. 3 has a denser division, and the second screen 22b has a more sparse division than the screen 21 of the first portion, the wide bands 24 on the screen 22a migrate as indi-cated by the arrow 30, and on the second screen 22b as indi-cated by the arrow 31, when the tape 11 is moved as indicated by the arrow 32. The division of the two screens 22a, 22b on the second portion can be of different relations to the division of the screen 21 of the fi.rst portion9 in which case the wide bands 24 will migrate at a greater speed over one of the two screens 22a, 22b than over the second one of the screens 22a, 22b.
At this embodiment a light diode 27 is provided for each of the two screens 22a, 22b, and in a corresponding way a phototransistor is provided for each of the screens 22a, 22b The resulting two interference patterns render it possible to record also the direction of movement of the tape 30. 11. It also is obvious, that a higher accuracy than at the ~irstmentioned embodiment can be achieved, because a phase comparision can be made between the interference patterns It was stated above, that the screen 21 o~ the ~irst portion preferably consists of opaque lines separated by light, pre~erably white lines The tape 11, however, can also be made of a transparent material, iD which case -the screen 21 applied to the tape 11 consists of opaque lines separated by transparent lines In this case, the light diode 27 and the phototransistor 28 are placed each on one side c>~ the screen 21, 22 o~ the two portions, in such a manner, that the light of the light diode 27 is transmitted through the screeD 21, 22 of the two portions and thereafter meets the phototransistor 28 This lastmentioned embodiment applies both when the screen 22 o~ the second por-tions consists of one screen 22 and when it consists o~ two - screens 22a, 22b When it consists o~ two screens ~2a, 22b, two light diodes 27 and two phototransistors 28 are used, as mentioned above Fig. 5 shows an example of an electric wiring diagram for geDerating electric pulses corresponding to the aforesaid light pulses. The light diode 27 and the amplifier 33 are supplied with a voltage applied over poles of the input 34.
The emitted light 35 of the light diode 27 passes in the manner stated above through the first and second screens 21, 2~ of the transmitter unit and meets the phototransistor 28 The resul-ting signal is amplied in three amplifyer steps, each contain-ing a transistor 36, 37, 38, The capacitor 39 is a feed-back capacitor.
The signal thus obtained is amplitude limited by a Zener diode 40 connected in parallel over the output. The out-put signal consisting of pulses is taken out via poles of the output 41.
When measuring is to be carried out, a switch 42 is moved to a position permitting the electronics associated with the measuring tape to receive voltage from a battery 43.
~ g~
Thereafter tha tape 11 is pulled out the necessary length, so that the hook 15 on the tape 11 and the re~erence hook 16 on the housing 13 corresponds to the length to be measured, While the tape 11 is being pulled out, the phototransistors 28 are met by a number of light pulses, which are converted to elec-tric pulses counted by a calculating unit ~4, The calculating unit, which can be of known type, is only schematically shown in ~ig. 1, Said calculating unit 44 thereafter converts in known manner the number of pulses to digital form and controls ; 10 a display 45, on which the distance between said two hooks 15, 16 is shown in figures, In Fig. 2 by way of example the dis-tance is shown to be 1243,56 mm. The calculating unit 44 at the preferred embodiment of the invention is designed iD known manner so that it receives two different pulsating electric voltages from the two phototransistors 28 and performs the aforesaid phase comparison. The calculating unit 44 preferably is designed to operate continuously, so that figures are shown all the time on said display 45 indicating the current distance between said hooks 15, 16.
After completed measurement, the tape 11 is reeled into the housing 13, and the switch 42 is moved to its breaking position.
For certain types of measuring it is practical to fold out the measuring tongue 18 for measuring between the hook 15 of the tape 11 and the hook 20 of the tongue, as mentioned above. The measuring tongue 15 preferably has a length of 50-100 mm when the tape meter 13 is intended for use at measur-ing distances up to about 2000 mm, The distance between the hook 20 of the measuring tongue 18 and the reference hook 16, for example, can be 100 mm. At measuring by means of the measuring tongue 18, the button 46 is pressed in, and the calculating unit 44 in known manner is designed to add 100 mm _g_ to the measure in question between the hook 15 and the refer-ence hook 16 on said display 45, The button 46 can be replaced by another switch, which automatically is actuated when the measuring tongue 18 is being folded out.
., ~ . , . . -
Known devices for automatic indication of measurements often are very complicated and cannot be taken along like a usual measurlng tape, but are i]ntended primarily for industrial use.
The present invention relates to a measuring tape, which is intended to be used as a normal measuring tape, for example as the known tape meter, and be taken along by a person, for example a private person for home-use or a craftsman at work, The present invention relates to an electronic measur-ing tape ~or automatic reading a measured length, which tape in non-operative position is stored on a spool in a housing, and for measuring can be pulled out of said housing, comprising a first and a second portion of a transmitter unit, which portions comprise screens consisting of opaq~e lines separated by light : 20 or transparent lines The invention is characterized in that the screen of the first portion is located on the measuring tape, and the screen o~ the second portion is located in said housing immedi-ately closely to the screen of the first portion, whereby an interference pattern, a so-called moir~ pattern, arises upon movement o~ the screen of the first portion relative to the screen of the second portion when viewing the screen o~ the first portion through the screen of the second portion, and that a reading means is provided to optically read said interference pattern.
The invention is described in the following, with re~erence to the accompanying drawing, in which 1~?9~
, Fig, 1 is a lateral view of a tape meter, to which the present invention is applied, Fig. 2 is a view from above of the tape meter, Fig 3 shows a first embodiment o~ the screen o~ the first and second portion, Fig. 4 shows a second embodiment of the screen of the first and second portion, Fig. 5 is an electric wiring diagram for converting light pulses to voltage pulses In Fig 1 a measuring tape in the form o~ a tape meter 10 is shown, which comprises a tape 11 supported in wound-up state in a spool 12 in a housing 13 about an axle 14 For measuring a length, the tape 11 is pulled out of the housing.
The terminating points of the measuring distance preferably consist of a hook 15 attached to the forward edge of the tape 11 and a reference hook 16 stationary on the housing 13, or some other suitable reference hook. Upon pulling the tape 11 out of the housing 13, energy is stored in a spring means (not shown), which in known manner causes the tape be reeled into the housing after completed measuring by action of said spring.
Furthermore, in known manner a pawl is provided, by which the tape 11 can be stopped in partially or fully pulled-out position In Fig. 1 the pawl is illustrated by a control button 17, which is pushed in to release the pawl and pulled out to actuate the pawl.
For certain kinds of measuring a tongue 18 can be folded out in known manner to a position in parallel with the tape 11 on the opposite side of the housing 13, as shown in Fig. 1. When the tongue is folded in, it is fitted into a groove ~not shoY~) in the housing 13 to a position indicated by the dashed line 19 in Fig. 1.
The measuring tongue 18 being in folded-out state, 991~2 measuring takes place between the hook 15 on the tape 11 and the hook 20 at the outer end of the measuring tongue 18 The tape 11 and measuring tongue 18 preferably are made of a steel material as used for usual tape meters The housing 13 preferably is made of a steel material or strong plastic material.
As mentioned above andl shown in Figs l, 2 and 3, the device according to the invention comprises a first portion 21 and a second portion 22 of a transmitter unit, which portions 21, 22 comprise screens The screen 21 of the ~irst portion is located on the upper surface of the tape ll in Fig 1, and the screen 22 of the second portion is stationary located in the housing 13 The screens of the first and second portion consist o~ opaque lines 23 separated by light or transparent lines. For the sa~e o~ clarity, only a ~ew opaque lines 23 are shown in the Figures.
When two screen consist o~ opaque lines separated by transparent interspaces, an interference patter, a so-called moiré pattern, arises when viewing a first screen through a second screen. Depending on the design of the two screens rela-tive to each other, di~ferent types o~ moiré pattern can be caused to arise According to the present inven~ion, the opaque lines 23 associated with the screen 21 o~ the ~irst portion are lo-cated substantially perpendicularly to the longitudinal direc-tion of the tape ll, and the opaque lines 23 associated with the screen 22 o~ the second portion are located substantially in parallel with the opaque lines 23 of the first portion 21 When the tape ll is being pulled out o~ the housing 13 for measuring a distance, and thereby the first screen 21 is moved perpendicularly to the opaque lines 23 on the second screen 22, an inter~erence pattern of migrating wide dark bands 99~l2 24 arises, for example as shown ln Fig 2, when viewing the first screen 21 through the second screen 22 According to the present invention, the screens 21, 22 are designed so that the screen 21 of the first portion has a division, i.e a number o~
opaque lines 23 per length unit perpendicular to the lines 23, which differs ~rom the division of the screen 22 of the second portion.
This difference in division preferably is obtained thereby, that the opaque lines 23 on the two portions 21, 22 have the same width, and that the width o~ the light or transparent lines in the screen 21 of the first portion is dif~erent from the width in the screen 22 of the second portion.
According to a modified embodiment, however, the width of the opaque lines 23 as well as the width of the light or transparent lines in the screen 21 of -the first portion are dif-ferent from the width in the screen 22 of the second portion.
By designing the screens 21, 22 as indicated above, an inter-~erence patterns is obtained which9 as stated, consists of wide dar~ bands 24 when the screen 21 of the tape moves relative to the screen 22 of the second portion.
The migration direction of the wide bands 24 depends on which of the two screens 21, 22 has the densest division.
Fig. 3 shows by way of example an embodiment where the screen 22 of the second portion has a denser division, i e a greater number of opaque lines 23 per length unit perpen-dicular to the l:ines 23, than the screen 21 o~ the ~irst por-tion. As a result thereof, the wide bands 24 migrate in a direction marked by the arrow 25 when the tape 11 is pulled in a direction marked by the arrow 26 When the screen 21, 22 of the first and second por-tion have a different division, the wide bands 24 will migrate through a distance, which is longer than the distance, through 99~2 which the tape 11 has moved. Thereby a ratio is obtained between the distance, through which the tape 11 moves, and the distance, through which the wide bands 24 move Consequently, the movement of the tape 11 can be read with higher accuracy by means of the migration of the wide ban~s 24 than by a reading directly against the tape 11.
The ratio thus obtained depends on the difference in division between the screen 21, Z2 of the first and second portion. In order to obtain a high ratio, i e. a great number of wide bands 2~ passing a point on the second screen 22 for a certaln movement of the tape 11, the difference in division between the screens 21, 22 of the two portions must be small, When, for example, the opaque lines 23 on the two screens 21, 22 have the same width, for example 0,6 mm, and ~he light or transparent lines therebetween have a width on one screen of 0,5 mm and on the second screen o~ 0,3 mm, a ratio of the magnitude of about 10 times is obtained, i.e. the wide bands 24 seem to migrate over the screen 21, 22 a distance 10 times longer than the distance ~hrough which the tape 11 was moved.
In this example, thus, is shown that a substantially higher accuracy with respect to the measuring of the movement of the tape 11 can be obtained by the device according to the inven-tion, compared with direct measuring on the tape 11 as, for example, in the case of a tape meter.
According to a preferred embodiment of the invention, the screen 21 of the first portion consists of opaque lines 23 separated by light, preferably white lines, and the screen 22 of the second portion consists of opaque lines 23 separated by transparent :Lines The second portion preferably is made of a transparent p:lastic material, on which said screen 22 has been applied.
A reading means provided in the housing 10 comprises 9~2 one or more light diodes 27 or the like for lighting the screens 21, 22 of the transmitter unit and one or more photo-transistors 28 or the like for recording the interference pat-tern or patterns According to the preferred embodiment, the light diode 27, or light diodes, and the phototransistor 28, or phototrans~
istors are located on that side of the screen 22 of the second portion which faces away from t~e screen 21 of the first por-tion.
When the screen 21, 22 of the first and second portion, respectively, consists of one screen, one light diode 27 and one phototransistor 28 are used.
At measuring and recording the interference pattern, the light diode 27 lights through the screen 22 of the second portion, whereby the light is reflected against the screen 21 of the first portion and further is transmitted through the screen 22 of the second portion to meet the phototransistor 28 When the tape 11 is being pulled out of the housing 13, thus, a plurality of migrating dark bands 24 will cause the light from the light diode 27 to meet the phototransistor 28 in the form of pulsating light. The phototransistor con-verts these light pulses to electric pulses, which are ampli-fied and processed in an electronic unit suitable for this purpose By arranging the screens 21, 22 of the two portions so that a high ratio of the aforesaid kind is obtained, a great number of electric pulses can be obtained from the phototrans-istor for a relative small movement of the tape 11.
It also appears from the aforesaid, that a high ac-curacy with respect to a distance, through which the ta~e 11is moved, is obtained with the device according to the present invention, without its components having to be designed with 9~
a corresponding high precision In order to obtain a very high accuracy, according to a further embodiment the screen of the first or second por-tion is di~ided into two screens The screen 22, for example, ` of the second portion consists of two screens 22a, 22b with different division, where the parti.tion line 23 between the screens 22a, 22b is perpendicular to the opaque lines 23 and located symmetrically on the second portion, as shown in Fig. 4, One of the two screens 22a, 22b has a division, which is denser than the division of the screen 21 of the first por-tion, and the second one of the two screens 22a, 22b has a division, which is more sparse than the division of the screen 21 of the first portion. When, for example, one screen 22a in Fig. 3 has a denser division, and the second screen 22b has a more sparse division than the screen 21 of the first portion, the wide bands 24 on the screen 22a migrate as indi-cated by the arrow 30, and on the second screen 22b as indi-cated by the arrow 31, when the tape 11 is moved as indicated by the arrow 32. The division of the two screens 22a, 22b on the second portion can be of different relations to the division of the screen 21 of the fi.rst portion9 in which case the wide bands 24 will migrate at a greater speed over one of the two screens 22a, 22b than over the second one of the screens 22a, 22b.
At this embodiment a light diode 27 is provided for each of the two screens 22a, 22b, and in a corresponding way a phototransistor is provided for each of the screens 22a, 22b The resulting two interference patterns render it possible to record also the direction of movement of the tape 30. 11. It also is obvious, that a higher accuracy than at the ~irstmentioned embodiment can be achieved, because a phase comparision can be made between the interference patterns It was stated above, that the screen 21 o~ the ~irst portion preferably consists of opaque lines separated by light, pre~erably white lines The tape 11, however, can also be made of a transparent material, iD which case -the screen 21 applied to the tape 11 consists of opaque lines separated by transparent lines In this case, the light diode 27 and the phototransistor 28 are placed each on one side c>~ the screen 21, 22 o~ the two portions, in such a manner, that the light of the light diode 27 is transmitted through the screeD 21, 22 of the two portions and thereafter meets the phototransistor 28 This lastmentioned embodiment applies both when the screen 22 o~ the second por-tions consists of one screen 22 and when it consists o~ two - screens 22a, 22b When it consists o~ two screens ~2a, 22b, two light diodes 27 and two phototransistors 28 are used, as mentioned above Fig. 5 shows an example of an electric wiring diagram for geDerating electric pulses corresponding to the aforesaid light pulses. The light diode 27 and the amplifier 33 are supplied with a voltage applied over poles of the input 34.
The emitted light 35 of the light diode 27 passes in the manner stated above through the first and second screens 21, 2~ of the transmitter unit and meets the phototransistor 28 The resul-ting signal is amplied in three amplifyer steps, each contain-ing a transistor 36, 37, 38, The capacitor 39 is a feed-back capacitor.
The signal thus obtained is amplitude limited by a Zener diode 40 connected in parallel over the output. The out-put signal consisting of pulses is taken out via poles of the output 41.
When measuring is to be carried out, a switch 42 is moved to a position permitting the electronics associated with the measuring tape to receive voltage from a battery 43.
~ g~
Thereafter tha tape 11 is pulled out the necessary length, so that the hook 15 on the tape 11 and the re~erence hook 16 on the housing 13 corresponds to the length to be measured, While the tape 11 is being pulled out, the phototransistors 28 are met by a number of light pulses, which are converted to elec-tric pulses counted by a calculating unit ~4, The calculating unit, which can be of known type, is only schematically shown in ~ig. 1, Said calculating unit 44 thereafter converts in known manner the number of pulses to digital form and controls ; 10 a display 45, on which the distance between said two hooks 15, 16 is shown in figures, In Fig. 2 by way of example the dis-tance is shown to be 1243,56 mm. The calculating unit 44 at the preferred embodiment of the invention is designed iD known manner so that it receives two different pulsating electric voltages from the two phototransistors 28 and performs the aforesaid phase comparison. The calculating unit 44 preferably is designed to operate continuously, so that figures are shown all the time on said display 45 indicating the current distance between said hooks 15, 16.
After completed measurement, the tape 11 is reeled into the housing 13, and the switch 42 is moved to its breaking position.
For certain types of measuring it is practical to fold out the measuring tongue 18 for measuring between the hook 15 of the tape 11 and the hook 20 of the tongue, as mentioned above. The measuring tongue 15 preferably has a length of 50-100 mm when the tape meter 13 is intended for use at measur-ing distances up to about 2000 mm, The distance between the hook 20 of the measuring tongue 18 and the reference hook 16, for example, can be 100 mm. At measuring by means of the measuring tongue 18, the button 46 is pressed in, and the calculating unit 44 in known manner is designed to add 100 mm _g_ to the measure in question between the hook 15 and the refer-ence hook 16 on said display 45, The button 46 can be replaced by another switch, which automatically is actuated when the measuring tongue 18 is being folded out.
., ~ . , . . -
Claims (11)
1. An electronic measuring tape for automatic reading of a measured length, which tape in a non-operative position is stored on a spool in a housing and for measuring is pulled out of said housing, comprising a first and a second portion of a trans-mitter unit, which portions comprise screens consisting of opaque lines separated by light or transparent lines whereby an inter-ference pattern, a so called moiré pattern, arises when viewing the screen of said first portion through the screen of said second portion and where reading means is provided to read said interference pattern, where the screen of the first portion is provided on the measuring tape, characterized in that the screen of the second portion is provided stationary in said housing immediately closely to the screen of the first position, and that said reading means comprises one or more light diodes or the like, placed close to the screen of the second portion, for lighting the screens of the transmitter unit and one or more phototransistors or the like, placed close to said diode, for recording said inter-ference pattern or patterns, which phototransistor is arranged to generate electric pulses at the output of an amplifier of the phototransistor at its recording of said pattern, which pulses are fed to a per se known calculating unit adapted to convert the number of said pulses to digital form and capable to control a per se known display on which the measured length, via pulses converted into digital form, is displayed in digital form.
2. An electronic measuring tape according to claim 1, characterized in that the screen of the first portion has a division, i.e. a number of opaque lines per length unit perpen-dicular to the lines, different from the division of the screen of said second portion.
3. An electronic measuring tape according to claim 1, characterized in that the opaque lines associated with the screen of the first portion are located substantially perpendicularly to the longitudinal direction of the measuring tape, and that the opaque lines associated with the screen of the second portion are located substantially in parallel with the opaque lines of the first portion.
4. An electronic measuring tape according to any of C1aims 1, 2 or 3, characterized in that the screen of the first or second portion consists of two screens with different division, where the partition line between the screens is perpendicular to the opaque lines.
5. An electronic measuring tape according to any of claims 1, 2 or 3, characterized in that the opaque lines on the two portions are of the same width, and that the width of the light or transparent lines in the screen of the first portion is different from the width in the screen of the second portion.
6. An electronic measuring tape according to any of claims 1, 2 or 3, characterized in that both the width of the opaque lines and the width of the light or transparent lines in the screen of the first portion are different from the width in the screen of said second portion.
7. An electronic measuring tape according to any of claims 1, 2 or 3, characterized in that the screen of the first portion consists of opaque lines separated by light, preferably white lines, and the screen of the second portion consists of opaque lines separated by transparent lines.
8. An electronic measuring tape according to any of claims 1, 2 or 3, characterized in that the reading means com-prises one or more light diodes or the like for lighting the screens of the transmitter unit, and one or more phototransistors or the like for recording the interference pattern or patterns.
9. An electronic measuring tape according to any of claims 1, 2 or 3, characterized in that the light diode, or light diodes, and the phototransistor, or phototransistors, are located on that side of the screen of the second portion which faces away from the screen of the first portion.
10. An electronic measuring tape according to claim 1, characterized in that the electric pulses occurring at the output of the amplifier of the phototransistor at its recording of the interference patterns are fed to a per se known calculating unit, which is adapted to convert the number of said pulses to digital form and capable to control a per se known display, on which the distance between a hook on the forward end of the tape and a reference hook on the housing is calculated by the calculating unit is displayed in digital form.
11. An electronic measuring tape according to claim 10, including a measuring tongue with a hook at its free end mounted on the housing, the measuring tongue adapted in use to extend in a direction opposite to the tape, and when used for measuring a distance between its hook and the hook of the measuring tape, the calculating unit is adapted to add to the distance in question between the hook of the measuring tape and the reference hook the distance between the reference hook and the hook of the measuring tongue on said display, when the calculating unit receives an im-pulse thereby that a button on the housing is depressed, or that the measuring tongue is being folded out.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE7611512-0 | 1976-10-15 | ||
| SE7611512A SE400642B (en) | 1976-10-15 | 1976-10-15 | ELECTRONIC CARPET TAPE |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1099912A true CA1099912A (en) | 1981-04-28 |
Family
ID=20329157
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA288,755A Expired CA1099912A (en) | 1976-10-15 | 1977-10-14 | Electronic measuring tape |
Country Status (12)
| Country | Link |
|---|---|
| US (1) | US4164816A (en) |
| JP (1) | JPS5383653A (en) |
| CA (1) | CA1099912A (en) |
| DE (1) | DE2746368A1 (en) |
| DK (1) | DK456877A (en) |
| ES (1) | ES463534A1 (en) |
| FI (1) | FI773046A (en) |
| FR (1) | FR2368011A1 (en) |
| GB (1) | GB1571245A (en) |
| NO (1) | NO146001C (en) |
| SE (1) | SE400642B (en) |
| SU (1) | SU955879A3 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5691923A (en) * | 1995-04-25 | 1997-11-25 | Levi Strauss & Co. | Digital measuring system |
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| US4161781A (en) * | 1977-11-25 | 1979-07-17 | The Stanley Works | Digital tape rule |
| DE3038716C2 (en) * | 1980-10-14 | 1985-12-12 | Dr. Johannes Heidenhain Gmbh, 8225 Traunreut | Position measuring device |
| CA1176456A (en) * | 1981-06-25 | 1984-10-23 | Walter K. Mansel-James | Tape measure |
| US4551847A (en) * | 1983-04-08 | 1985-11-05 | Caldwell W Kenneth | Hand held digital measuring device |
| DE3326137C2 (en) * | 1983-07-20 | 1994-01-20 | Bayerische Masindustrie Arno K | Tape measure |
| FR2554918B1 (en) * | 1983-11-10 | 1988-07-29 | Jaluzot Yves | METHOD AND DEVICE FOR OBTAINING NUMERICAL COORDINATES OF A POINT OR A SET OF POINTS |
| GB2172576A (en) * | 1984-12-18 | 1986-09-24 | Rabone Chesterman Ltd | Measuring tape housing |
| JPS61160007A (en) * | 1985-01-08 | 1986-07-19 | Kyoto Doki Kk | Digital tape measure |
| JPS61167808A (en) * | 1985-01-18 | 1986-07-29 | Kyoto Doki Kk | Digital measuring tape |
| US4575944A (en) * | 1985-06-19 | 1986-03-18 | Patrick Lin | Electronic digital tape-rule |
| WO1989009379A1 (en) * | 1986-07-08 | 1989-10-05 | Peter Sing | Apparatus for photoelectrically generated physical measurements |
| WO1988000776A1 (en) * | 1986-07-19 | 1988-01-28 | Ronald James Care | Linear measuring devices |
| GB2194042A (en) * | 1986-08-14 | 1988-02-24 | Bicc Plc | Displacement measurement |
| DE3715908A1 (en) * | 1987-05-13 | 1988-12-01 | Messerschmitt Boelkow Blohm | Device for length measurement |
| GB2217459A (en) * | 1988-04-13 | 1989-10-25 | Fanfare Electronics Limited | Improvements in or relating to a tape measure |
| DE3911754A1 (en) * | 1989-04-11 | 1990-10-18 | Wolfgang Kenter | Tape measure with bar code length markings and digital reader - has bar codes arranged transversely across tape, each containing defined length marking |
| US5060394A (en) * | 1989-04-20 | 1991-10-29 | Homestar International Inc. | Measuring apparatus with readout display |
| US5027526A (en) * | 1989-06-02 | 1991-07-02 | Crane R Stephen | Digital linear measuring device |
| US5142793A (en) * | 1989-06-02 | 1992-09-01 | Contek Corporation | Digital linear measuring device |
| US5414943A (en) * | 1993-11-12 | 1995-05-16 | Vogt; Katie | Anatomical measuring tape with indicator |
| US6276069B1 (en) | 1999-03-01 | 2001-08-21 | Jockey International, Inc. | Brassiere sizer |
| DE10312045B4 (en) * | 2003-03-18 | 2014-07-31 | Anton Rodi | Measuring system for absolute value recording of angles and paths |
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| DE202005011814U1 (en) * | 2005-07-25 | 2006-08-31 | Hoechstmass Balzer Gmbh | Electronic tape measure and this comprehensive length measuring device |
| CN100462665C (en) * | 2006-06-07 | 2009-02-18 | 宁波长城精工实业有限公司 | Electric band tape |
| US20080072446A1 (en) * | 2006-09-26 | 2008-03-27 | A Te Hu | Tape measure having digital output |
| US9080849B2 (en) | 2011-07-29 | 2015-07-14 | Milwaukee Electric Tool Corporation | Tape measure |
| CA2784047C (en) | 2011-07-29 | 2015-08-11 | Milwaukee Electric Tool Corporation | Tape measure |
| US8863399B2 (en) | 2011-08-26 | 2014-10-21 | Milwaukee Electric Tool Corporation | Tape measure |
| US9267778B2 (en) | 2012-01-19 | 2016-02-23 | Milwaukee Electric Tool Corporation | Tape measure |
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| USD733597S1 (en) | 2012-07-30 | 2015-07-07 | Milwaukee Electric Tool Corporation | Tape measure |
| USD785475S1 (en) | 2015-12-10 | 2017-05-02 | Milwaukee Electric Tool Corporation | Tape measure |
| USD785476S1 (en) | 2015-12-10 | 2017-05-02 | Milwaukee Electric Tool Corporation | Tape measure |
| USD787347S1 (en) | 2016-01-07 | 2017-05-23 | Milwaukee Electric Tool Corporation | Tape measure |
| USD783429S1 (en) | 2016-01-07 | 2017-04-11 | Milwaukee Electric Tool Corporation | Tape measure |
| USD783430S1 (en) | 2016-01-07 | 2017-04-11 | Milwaukee Electric Tool Corporation | Tape measure |
| USD788611S1 (en) | 2016-06-01 | 2017-06-06 | Milwaukee Electric Tool Corporation | Tape measure |
| CN107388914A (en) * | 2017-08-02 | 2017-11-24 | 王振兴 | digital tape measure |
| US10859363B2 (en) | 2017-09-27 | 2020-12-08 | Stanley Black & Decker, Inc. | Tape rule assembly with linear optical encoder for sensing human-readable graduations of length |
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| CA719410A (en) * | 1965-10-12 | T. Shepherd Alexander | Measuring apparatus | |
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| US3780440A (en) * | 1971-07-21 | 1973-12-25 | Ideal Aerosmith Inc | Measuring instrument |
| US3816002A (en) * | 1972-10-10 | 1974-06-11 | H Wieg | Apparatus for measuring displacement between two relatively movable members |
| US4031360A (en) * | 1975-11-17 | 1977-06-21 | The Raymond Lee Organization, Inc. | Electronic read out tape measure |
-
1976
- 1976-10-15 SE SE7611512A patent/SE400642B/en unknown
-
1977
- 1977-10-11 US US05/840,849 patent/US4164816A/en not_active Expired - Lifetime
- 1977-10-13 FR FR7730911A patent/FR2368011A1/en active Granted
- 1977-10-13 DK DK456877A patent/DK456877A/en not_active Application Discontinuation
- 1977-10-13 GB GB42649/77A patent/GB1571245A/en not_active Expired
- 1977-10-14 NO NO773527A patent/NO146001C/en unknown
- 1977-10-14 DE DE19772746368 patent/DE2746368A1/en not_active Withdrawn
- 1977-10-14 JP JP12338677A patent/JPS5383653A/en active Pending
- 1977-10-14 FI FI773046A patent/FI773046A/en not_active Application Discontinuation
- 1977-10-14 ES ES463534A patent/ES463534A1/en not_active Expired
- 1977-10-14 CA CA288,755A patent/CA1099912A/en not_active Expired
- 1977-10-14 SU SU772539352A patent/SU955879A3/en active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5691923A (en) * | 1995-04-25 | 1997-11-25 | Levi Strauss & Co. | Digital measuring system |
Also Published As
| Publication number | Publication date |
|---|---|
| DK456877A (en) | 1978-04-16 |
| ES463534A1 (en) | 1978-07-01 |
| SE400642B (en) | 1978-04-03 |
| FR2368011B1 (en) | 1983-09-09 |
| FI773046A (en) | 1978-04-16 |
| JPS5383653A (en) | 1978-07-24 |
| NO773527L (en) | 1978-04-18 |
| DE2746368A1 (en) | 1978-04-20 |
| NO146001B (en) | 1982-03-29 |
| SU955879A3 (en) | 1982-08-30 |
| NO146001C (en) | 1982-07-21 |
| US4164816A (en) | 1979-08-21 |
| GB1571245A (en) | 1980-07-09 |
| FR2368011A1 (en) | 1978-05-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |