CN2107648U

CN2107648U - Portable pocket electric balance

Info

Publication number: CN2107648U
Application number: CN 91228789
Authority: CN
Inventors: 马习武; 张相臣; 冯峰; 李东生
Original assignee: 马习武
Priority date: 1991-11-16
Filing date: 1991-11-16
Publication date: 1992-06-17

Abstract

The utility model relates to a portable pocket electric balance, which adopts a weighing sensor with capacitance type; the sensor is composed of an elastic bellow 6, two metal sleeves 8, 9 of an upper one and a lower one that are concentrically sheathed, and a balance hook 10 which is positioned at the centre of the circle of two sleeve tubes. The cargo arranged on the balance hook is heavier, the overlapping of the two metal sleeve tubes are more, and the capacitance value is bigger; inversely, the capacitance value is smaller. The weighing signal output by the sensor is delivered to an A/D converter for A/D transmitting after the signal is processed, and seven sections of code signal output by the A/D converter is delivered to a display device for display. The electronic balance has the advantages of simple structure and low cost.

Description

Portable pocket electric balance

The utility model is a kind of portable pocket-size electronic scale.

At present, the focus of development small-size electronic scale is the problem that solves LOAD CELLS, in prior art, it all is to adopt foil gauge as LOAD CELLS that many small-size electronic scales are arranged, though this sensor is simple in structure, power consumption is big, linear setting range is narrow, be unfavorable for signal Processing and circuit reduction, therefore, fail to obtain practical application.In addition, existing small-size electronic scale only limits to function of weighing, and does not have computing function.

The purpose of this utility model provides a kind of portable pocket-size electronic scale that adopts electric capacity as LOAD CELLS, the power consumption hardly of this capacitance type sensor, and linear setting range is wide.

Solution of the present utility model is as follows: this electronic scales has a shell, display screen is arranged on shell, LOAD CELLS is housed in the enclosure, signal processing circuit, A/D converter and battery etc., described LOAD CELLS is a kind of capacitance type sensor, it has a corrugated tube, this corrugated tube is gone to the bottom and is fixed on the shell lower shoe, the affixed insulcrete in corrugated tube upper end, in corrugated tube, be provided be nested with one heart on, following two metal sleeves are as two electrodes of capacitance type sensor, the upper end of last metal sleeve is fixed on the insulcrete, the lower end of following metal sleeve is fixed on the shell lower shoe, this sensor also has a steelyard hook, the steelyard hook afterbody is positioned at the circle centre position of two metal sleeves, the steelyard hook tail end is fixed on the insulcrete, the hook of its head is positioned at the shell bottom plate bottom, be provided with the fixture that a restriction steelyard hook surface level rocks in the metal sleeve down, described signal processing circuit has a fixed oscillator and a variable oscillator, described capacitance type sensor is connected in the variable oscillator as variable capacitance, and by oscillation period of the output terminal of fixed oscillator control variable oscillator, output terminal at two oscillators is connected to a both-end input and door, is connected to a voltage divider and a wave filter at the output terminal with door.

An input of described both-end and the door output pulse signal that dutycycle changes with weight change are admitted to A/D converter through dividing potential drop and filtering and carry out the A/D conversion, and A/D converter is directly exported seven sections and shown that sign indicating number sends into display and carry out numeral demonstration; If at the interface circuit of the electronic calculator of output termination of A/D converter and the movement of electronic calculator, then this electronic scales can have computing function.

Above-mentioned capacitance type sensor not power consumption substantially, and linear setting range is wide, and simple in structure, cost is low, and signal processing circuit is simplified, and cost reduces.

Describe in detail according to embodiment below.

Fig. 1, the shape assumption diagram of embodiment 1.

Fig. 2, the shape assumption diagram of embodiment 2.

Fig. 3, the structural representation of capacitance type sensor.

Fig. 4, the electronic-circuit diagram of signal processing circuit and A/D converter.

Fig. 5, the interface circuit figure of electronic calculator.

Referring to Fig. 1, in the front of shell 1 digital display screen 2 is housed, zeroing is housed on the shell left plate allowances for bark turn-knob 3, power switch 4 is housed on the shell right plate, be provided with carrying handle 5 on the top of shell.Goods is colluded on steelyard hook, mention carrying handle 5, gravimetric value is presented on the display screen at once.

Referring to Fig. 3, capacitive transducer has a corrugated tube 6, the corrugated tube lower end is fixed on the shell lower shoe, its affixed insulcrete 7 in upper end,

metal sleeve

8,9 is fixed in respectively on insulcrete and the shell lower shoe up and down, steelyard hook 10 is fixed on the insulcrete, and the cylindrical fixture of a steelyard hook is arranged in running casing 9, and restriction steelyard hook surface level rocks.According to the weight of the thing of being borrowed money, the compressed degree difference of corrugated tube, the overlapping degree that makes two metal sleeves is also different, and goods weighs more that two metals are overlapping must be many more, and capacitance is big more, on the contrary capacitance is more little.

Referring to Fig. 4, be connected into two Schmidt's oscillators 11 respectively by two Sheffer stroke gates, 12, oscillator 11 is fixed oscillator, the pulse signal that the output cycle is certain, oscillator 12 is variable oscillators, variable capacitance 13 is represented capacitive transducer, an input end of the output terminal of fixed oscillator and variable oscillator joins, make the oscillation period of two oscillators identical, their output terminal be connected to one with door 14, it with the signal of two oscillators carry out logic " with ", when the capacitance of variable capacitance 13 is big, also increase with the dutycycle of door 14 output pulse signals, otherwise its dutycycle reduces thereupon thereupon.Be admitted to the V of A/D sheet 7126 through dividing potential drop and filtering with the signal of door 14 output _IHPin carries out the A/D conversion, and 7126 devices are directly exported three and half seven segment code shows signal, sends into display screen 15 and carries out the numeral demonstration.7126 devices are to belong to differential input, and the dividing potential drop by constant current source 16 and variable resistor 17 provides the V that reference voltage is sent into 7126 devices _ILPin, when zeroing is allowanced for bark, but turn-knob is allowanced for bark in the turn zeroing, promptly is to adjust variable-resistance output valve, thereby changes V _ILThe input of pin reference voltage.

Referring to Fig. 2, if the computing function of setting up needs to add at outer casing frontispiece the keyboard of electronic calculator, the display screen of outer casing frontispiece adopts the display screen of this counter, a switch 18 also need be set on carrying handle, when mentioning carrying handle, switch 18 closures, this moment the display shown numeral gravimetric value of thing of being borrowed money, after unclamping carrying handle, switch 18 disconnects, and display keeps gravimetric value, at this moment can calculate price of goods by keyboard operation.

Referring to Fig. 5, be connected to the interface circuit of an electronic calculator and the movement of slim calculator at the output terminal of A/D sheet, as 838 counters.Constitute five multi-way switchs by the CD4052 sheet seven segment code of 7126 devices output is carried out gating, constitute a sequential circuit by two d

type flip flops

20,21, and by the gating sequential of the Q output terminal control multi-way switch of these two d type flip flops.Output terminal at multi-way switch constitutes seven by five phase inverters and ten 5G805 devices---ten code translators, seven segment code to multi-way switch output is deciphered, be connected to one and select bond switching in that each digital output end of code translator is all corresponding, respectively select digital keys corresponding on bond switching and the calculator keyboard and connect by what the CD4066 device constituted.According to the control of sequential circuit to multi-way switch, multi-way switch is the seven segment code of output tens digit top digit earlier, through seven---after ten decodings, connect the bond switching that selects of corresponding numeral, then this numeral is presented on the display, multi-way switch is exported seven end sign indicating numbers of time low level, low order digit in proper order then, is displayed on the display through same working routine.Between hundred and tens word, produce radix point by sequential circuit control, it is the Q end output high level useful signal of d type flip flop 21, through a differentiating circuit bond switching 25 that selects of corresponding radix point is connected, when goods was taken off, the Q of d type flip flop 21 end output reset signal was connected the bond switching 26 that selects of corresponding reset key " CE " through differentiating circuit, then be shown as zero, can weigh once more.In sequential circuit, also having a peace to turn round 23 promptly is the switch on the carrying handle 18 among Fig. 2, peace is twisted joint when leading to, and provides zero level with door 24, then the interface circuit operate as normal, be that weighing-up wave is admitted to the display screen demonstration through interface circuit, when peace twists off out, provide the malleation reset signal with door, interface circuit zero setting, and gravimetric value is retained on the display screen, but price of goods is calculated in keyboard operation this moment.

Embodiment 2 of the present utility model has set up computing function, and it is convenient that this electronic scales is used, and receives praises from customers.

Claims

1, portable pocket-size electronic scale has a shell 1, and display screen 2 is arranged on shell, and LOAD CELLS, signal processing circuit, A/D converter and battery etc. are housed in the enclosure, it is characterized in that:

A. described LOAD CELLS is a kind of capacitance type sensor, it has a corrugated tube 6, this corrugated tube is gone to the bottom and is fixed on the shell lower shoe, the affixed insulcrete 7 in corrugated tube upper end, in corrugated tube, be provided be nested with one heart on, following two metal sleeves 8,9 two electrodes as capacitance type sensor, the upper end of last metal sleeve is fixed on the insulcrete, the lower end of following metal sleeve is fixed on the shell lower shoe, this sensor also has a steelyard hook 10, the steelyard hook afterbody is positioned at the circle centre position of two metal sleeves, the steelyard hook tail end is fixed on the insulcrete, the hook of its head is positioned at the shell bottom plate bottom, be provided with the fixture that a restriction steelyard hook surface level rocks in the metal sleeve down

B. described signal processing circuit has a fixed oscillator 11 and a variable oscillator 12, described capacitance type sensor is connected in the variable oscillator as variable capacitance, and by oscillation period of the output terminal of fixed oscillator control variable oscillator, output terminal at two oscillators is connected to a both-end input and door, is connected to a voltage divider and a wave filter at the output terminal with door.

2, electronic scales as claimed in claim 1, it is characterized in that: the interface circuit that is connected to an electronic calculator at the output terminal of A/D converter, and set up the movement of electronic calculator, the keyboard of electronic calculator is set on shell, described interface circuit has a multi-way switch that seven sections demonstration sign indicating numbers is carried out gating, the sequential circuit that strobe pulse is provided for multi-way switch, seven segment code to multi-way switch output carries out seven of decimal system decoding---ten code translators, each digital output end of this code translator all is connected to and selects bond switching, each selects the keyswitch of corresponding numeral on bond switching and the electronic calculator and connects, comprise also in the described sequential circuit that a radix point signal generating circuit and reset signal produce circuit, their output terminal is connected to one respectively and selects bond switching, these two select bond switching respectively with calculator keyboard on radix point button and zero clearing button and connect, also comprise another button clear circuit at sequential circuit, the zero clearing button in this circuit is installed on the carrying handle 5 as switch 17.