1. Field of the Invention
The present invention is relevant to a transmitter unit for measuring instruments. More specifically, the present invention is relevant to a transmitter unit for measuring instruments that transmits measurement data measured by measuring instruments such as vernier caliper, depth gauge, and so on to external data processing instruments by wireless.
2. Description of Related Figure
Measurement data acquisition/processing systems are conventionally known, where each measurement terminal transmits measurement data to data processing instruments, and the data processing instruments calculate quality control data or statistic data by means of collecting and processing the measurement data transmitted from each measurement terminal.
Above all, in a system where each measurement terminal transmits measurement data by wireless (wireless measurement data transmission system), each measurement terminal needs to be equipped with a wireless transmitter unit respectively.
As a measurement terminal equipped with a wireless transmitter unit, a vernier caliper shown in FIG. 7 is conventionally known, which consists of a electronic vernier caliper 1 and a transmitter unit 3 connected through a connection cable 2.
The electronic vernier caliper 1 consists of a main beam 12 and a slider 14 travelling along the main beam 12. The main beam 12 has an inner measuring jaw 11A and an outer measuring jaw 11B on the end. The slider 14 has an inner measuring jaw 13A and an outer measuring jaw 13B on the end to measure an artifact together with the jaw 11A or 11B by contact. The slider 14 is equipped with an electric hardware module for electronic vernier caliper.
As detail of the electric hardware module for electronic vernier caliper, the slider 14 is equipped with a signal processor 17 inside, a digital display 16 on front, and an output connector 18 on top. The signal processor 17 calculates travelling displacement of the slider 14 (measurement data) by processing signal from an incremental or absolute position sensor 15 fitted between the main beam 12 and the slider 14 to detect travelling displacement of the slider 14 along the main beam 12. The digital display 16 displays measurement data calculated by the signal processor 17. The output connector 18 outputs measurement data calculated by the signal processor 17 to the transmitter unit 3 through the connection cable 2.
The vernier caliper shown on FIG.7 is operated as follows. Contact the inner measurement jaw 11A, 13A or the outer measurement jaw 11B, 13B with an measurement artifact by travelling the slider 14 along the main beam 12 on condition that the transmitter unit 3 is connected with the output connector 18 on the slider 14 through the connection cable 2. Then, travelling displacement of the slider 14, in other words, dimension between the inner measurement jaw 11A and 13A or the outer measurement jaw 11B and 13B (measurement data) is digitally displayed on the digital display 16. By pressing a transmission command switch (not shown) here, the measurement data is transmitted from the transmitter unit 3 by wireless.
However, according to the vernier caliper structure equipped with a conventional wireless transmitter unit, the connection cable 2 may obstruct measurement when travelling the slider 14 along the main beam 12.
It is an idea to fix the transmitter unit 3 onto the slider 14 by using special fixing means since it is inconvenient to carry the electronic vernier caliper 1 with which the transmitter unit 3 is danglingly connected through the connection cable 2. However, a special fixing mean to fix the transmitter unit 3 onto the slider 14, besides the connection cable 2 to connect the electronic vernier caliper 1 with the transmitter unit 3 electrically, causes inevitable increase of number of components and cost.
In addition, the fixing work is difficult because the transmitter unit 3 has to be firmly fixed onto the slider 14 not to be obstructive to measurement. Furthermore, even if the transmitter unit 3 is firmly fixed onto the slider 14, measurement may still be obstructed by interference between a measurement artifact and the transmitter unit 3 in case that profile of the transmitter unit 3 protrudes beyond front profile of the slider 14.
This problem occurs not only in case of a vernier caliper but also other instruments, such as depth gauge (depth measuring instrument) or linear scale unit (linear displacement sensor), which measures dimensions of an artifact from the slider travelling displacement along the main beam, thickness gauge (thickness measuring instrument), which measures thickness of an artifact from the spindle travelling displacement against the frame in axial direction, and so on.
The object of the present invention is to provide a transmitter unit for measuring instruments which can overcome above conventional problem, in other words, which is not obstructive to measurement, does not cause increase of number of components, and can be attached onto measuring instruments firmly and easily.
In order to attain aforementioned object, the transmitter unit for measuring instruments on the present invention is to be attached to measuring instruments that have a main beam and a slider travelling along the main beam. As for detail of the measuring instruments, the slider has a signal processor to calculate measurement data based on the slider travelling displacement along the main beam and an output connector to output measurement data calculated by the signal processor. The transmitter unit for measuring instruments on the present invention is characterized as follows. The transmitter unit consists of a main unit, which accommodates a transmission circuit inside to transmit measurement data by wireless, and an attachment module to retain the main unit attachably and detachably on the slider. The attachment module, which is constituted to be plugged into and unplugged from the output connector on the slider, has a connector to connect the transmission circuit in the main unit with the output connector on the slider.
In this structure, by inserting the attachment module into the output connector on the slider, the transmission circuit in the main unit is electrically connected with the output connector on the slider automatically as well as the main unit is mechanically retained onto the slider.
In other words, mechanical means to retain the main unit onto the slider works also as electrical means to connect the transmission circuit in the main unit with the output connector on the slider. Accordingly, the transmitter unit can be attached firmly and easily only by inserting the attachment module into the output connector on the slider without using any extra components. In addition, this cableless structure can keep measurement free from obstruction by connection cables.
Also, the transmitter unit for measuring instruments on the present invention is to be attached to measuring instruments that have a main beam and a slider equipped with a digital display in addition to a signal processor and an output connector aforementioned above. The digital display displays the measurement data calculated by the signal processor. In this case, the attachment module retains the main unit attachably and detachably on second side of the slider opposite to first side on which the digital display is located. Further, the transmitter unit for measuring instruments on the present invention is characterized by that the main unit profile is formed at least not to protrude beyond first side profile of the slider on condition that the main unit is retained onto second side of the slider, in addition to the aforementioned characters.
This structure can keep measurement free from obstruction by interference between a measurement artifact and the main unit, besides the aforementioned effects, since the main unit profile at least does not protrude beyond first side profile of the slider (side equipped with the digital display).
On the above explanation, any measuring instrument that has a main beam and a slider travelling along the main beam is applicable.
A vernier caliper that has a main beam with jaws and a slider travelling along the main beam with jaws to measure an artifact together with jaws on the main beam by contact is an example. On the vernier caliper, the slider has a signal processor to calculate measurement data based on the slider travelling displacement along the main beam, a digital display to display measurement data calculated by the signal processor, and an output connector to output measurement data calculated by the signal processor. So is a linear scale unit (linear displacement sensor) or the like that has similar structure.
The attachment module may be any kind of constitution so long as that can retain the main unit onto the slider. However, on the present invention, the attachment module consists of a first retainer and a second retainer to be plugged into and unplugged from the output connector on the slider as follows. The first retainer is extended from the main unit striding over the slider. The second retainer is extended square from the first retainer end and parallel to the main unit. The second retainer has a connector on the end to be connected with the output connector on the slider.
In this structure, the transmitter unit can be easily attached and firmly retained only by inserting the second retainer into the output connector on the slider from right above. Also, the transmitter unit can easily be detached by pulling off in the reverse direction. Accordingly, the transmitter unit can be easily retrofitted to existing electronic vernier caliper equipped with output connector or any other similar measuring instruments.
The transmitter unit may accidentally come off from the slider on this retention condition if force in reverse direction of insertion is applied to the main unit. In order to protect from this accident, a locking means to restrict movement of the transmitter unit in direction of the second retainer coming off from the output connector is provided on a side of the main unit opposite to a side on which the first retainer fitted.
Concretely, the locking means consists of a guide groove on the main unit and a locking piece sliding along the guide groove. The guide groove is formed toward the slider on a side of the main unit opposite to a side on which first retainer is fitted. By sliding along the guide groove, the locking piece can projects and retracts over fourth side of the slider opposite to third side on which the output connector is located. By this mechanism, the transmitter unit can be protected from coming off from the slider in simple structure as the locking piece slid along the guide groove and projected over the fourth side of the slider restricts movement of the main unit in direction of coming off from the slider.
On this locking means, the locking piece can be fixed to the slider not to come off from the guide groove. Accordingly, the coming-off protection mentioned above can be more reliable.
In the transmitter unit structure mentioned above, the attachment module may be constituted integrally with the main unit. However, on the present invention, the attachment module is constituted as a separate unit, which can be coupled and decoupled with the main unit through a coupling mechanism.
In this constitution, both the main unit and the attachment module has a connector, which is coupled automatically when the attachment module is fitted to the main unit. Since this constitution provides electrical connection when the attachment module is fitted to the main unit, no special wiring arrangement needs to be provided. Accordingly, it is easy to assemble the transmitter unit.
In addition, the coupling mechanism consists of retaining snaps on either the main unit or the attachment module and engaging holes to be coupled with the snaps on the other. Accordingly, the attachment module can be coupled and decoupled with the main unit in simple structure.
Further, the main unit consists of a pair of separable case halves, containing transmission circuit inside, which has at least one retaining snap each. Accordingly, the three parts (a pair of the case halves and the attachment module) can be integrally assembled by putting the retaining snaps on the main unit case halves into the engaging holes on the attachment module after the case halves are coupled.
As mentioned before, the attachment module consists of a first retainer, which is extended from the main unit striding over the slider, and a second retainer to be plugged into and unplugged from the output connector on the slider, which is extended square from the first retainer end and parallel to the main unit. In order to provide ergonomic operation in this structure, a switch to send data transmission command to the transmission circuit is located on the first retainer.
More than one function can be operated with this single switch by means of duration control. Concretely, transmitting measured data, canceling transmitted data, and setting unique ID for each transmitter unit can be controlled in accordance with duration of the switch operation.
Further, an indicator device (or light indicator, such as LED=light-emitting diode, EL=electro-luminescent display, laser display, and electric lamp) responding on the switch operation is located on a same side of the first retainer as display side of the digital display on the slider. Accordingly, the switch operation can be monitored in same view as reading measurement data on the digital display.
The transmitter unit for measuring instruments on the present invention can be applied not only to measuring instruments that have a main beam and a slider travelling along the main beam but also to other kind of measuring instruments, such as thickness gauges (thickness measuring instruments) or micrometers, which has a frame and a spindle travelling against the frame.