CN203432656U - Multi-head combination scale - Google Patents

Abstract

The utility model discloses a multi-head combination scale which can prevent the weighing accuracy from being influenced by material stacking on a weighing hopper hanger. The multi-head combination scale comprises an aluminum box, a buffer hopper, a weighing hopper, two stepping motors and weighing elements, wherein the buffer hopper and the weighing hopper are disposed on the outer side of the aluminum box and are placed from top to bottom, and the two stepping motors and the weighing elements are disposed on the inner side of the aluminum box and are placed from top to bottom. The weighing elements mainly comprise an upper sensor fixing member, a lower sensor fixing member, a weighing sensor, a sensor protecting member, a weighing hopper hanger and a measuring circuit. The weighing hopper hanger is composed of a hanger supporting plate I, a hanger supporting plate II and a I hanger supporting plate III, wherein the hanger supporting plate I, the hanger supporting plate II and the I hanger supporting plate III are welded together through touch welding, and the two sides of the hanger supporting plate I are hollowed out. By the adoption of the design, the area of the contact plane can be reduced, and materials can be prevented from falling on the weighing hopper hanger, thereby reducing interference to the weighing sensor and improving the accuracy of weighing.

Description

A kind of bull combination balance

Technical field

The utility model relates to a kind of bull combination balance, is specifically related to a kind ofly prevent that the bull combination balance hopper suspension member stacking material of weighing from affecting the mechanism of its weighing precision.

Background technology

Bull combination balance is a kind of weighing device being comprised of oscillation feed gear, a plurality of independently weighing unit and collecting mechanism, it utilizes permutation and combination principle that the weight of weighing unit is carried out to automatically preferential combination and calculates, and the weight that draw the best, approaches target weight value is most carried out assembly packaging.

The existing bull combination balance hopper suspension member of weighing adopts (Fig. 3) this form, the shortcoming of this suspension member to be to adopt dull and stereotyped integrated method processing, has a smooth plane after machine-shaping.Machine, in weighing the process of fine particle shape material or powder material, is easy to have material and drops on the hopper suspension member of weighing by the space of vibrating disk or the gap of hopper.In the weighing process of this type objects, if weighed, on hopper suspension member, fall to have material, and in the process of using, fail to dispose in time the material of weighing on hopper suspension member, will have influence on the target weight value that machine is weighed, cause the most at last the accuracy of machine inaccurate.

Utility model content

The purpose of this utility model is to provide a kind of a kind of bull combination balance that prevents from affecting because of the hopper suspension member stacking material of weighing weighing precision.

The utility model is achieved through the following technical solutions: a kind of bull combination balance, comprises aluminium box, is positioned at the buffering hopper of placing in aluminium box outside from top to bottom and weighs hopper and two stepper motors that are positioned at that aluminium box inner side places from top to bottom and loading component; Loading component mainly comprises fixture under sensor upper fixing element, sensor, LOAD CELLS, sensor protection part, weigh hopper suspension member and metering circuit; the described hopper suspension member of weighing is comprised of suspension member support plate one, suspension member support plate two and suspension member support plate three; described suspension member support plate one, suspension member support plate two and suspension member support plate three adopt butt-joint integrally welded; the structure that described suspension member support plate one is emptied for both sides; by this design, can reduce contact plane; prevent that material from dropping on the hopper suspension member of weighing, thereby reduce the interference to LOAD CELLS.

Under described LOAD CELLS front and back and sensor upper fixing element, sensor, fixture is bolted and is integral, and wherein one end is fixed on aluminium box, and the other end is connected with the hopper suspension member of weighing.

Described LOAD CELLS is resistance strain gage, resistance strain gage is attached on flexible member, metering circuit is connected with resistance strain gage, and when flexible member stress deformation, thereby the resistance strain gage being attached on flexible member also produces the resistance that distortion changes resistance strain gage accordingly.

The beneficial effects of the utility model are: a kind of bull combination balance hopper suspension member stacking material that can prevent from weighing is provided, thereby has improved the accuracy weighing.

Accompanying drawing explanation

Fig. 1 is structural representation of the present utility model;

Fig. 2 is side view of the present utility model;

Fig. 3 is the hopper hanger structure schematic diagram of weighing of existing a kind of bull combination balance;

Fig. 4 is the hopper hanger structure schematic diagram of weighing of the present utility model;

In figure: 1 aluminum hull, 2 buffering hoppers, 3 weigh fixture under hopper, 4 stepper motors, 5 sensor upper fixing elements, 6 sensors, 7 LOAD CELLS, 8 sensor protection parts, 9 weigh hopper suspension member, 21 suspension member support plates one, 22 suspension member support plates two, 23 suspension member support plates three.

Embodiment

In order further to understand feature of the present utility model and technology contents, below in conjunction with specific embodiment and Figure of description, the utility model is further elaborated and is illustrated:

As shown in Figure 1, Figure 2 or shown in Fig. 4, a kind of bull combination balance that the utility model provides, comprises aluminium box 1, is positioned at the buffering hopper 2 of placing in aluminium box 1 outside from top to bottom and weighs hopper 3 and two stepper motors 4 that are positioned at that aluminium box 1 inner side places from top to bottom and loading component, loading component mainly comprises sensor upper fixing element 5, under sensor, fixture 6, LOAD CELLS 7, sensor protection part 8, weigh hopper suspension member 9 and metering circuit, the described hopper suspension member 9 of weighing is by suspension member support plate 1, suspension member support plate 2 22 and suspension member support plate 3 23 form, described suspension member support plate 1, suspension member support plate 2 22 and suspension member support plate 3 23 adopt butt-joint integrally welded, the structure that described suspension member support plate 1 is emptied for both sides, by this design, can greatly reduce contact plane, prevent that material from dropping on the hopper suspension member of weighing 9, thereby reduce the interference to LOAD CELLS 7.

Under LOAD CELLS 7 front and back and sensor upper fixing element, sensor, fixture is bolted and is integral, and wherein one end is fixed on aluminium box 1, and the other end is connected with the hopper suspension member 9 of weighing.LOAD CELLS 7 is resistance strain gage, and resistance strain gage is attached on flexible member, and metering circuit is connected with resistance strain gage, and when flexible member stress deformation, the resistance strain gage being attached on flexible member also produces distortion accordingly.

This combination balance is by the line machine vibration that shakes, by amplitude and line, shake and reinforced material is delivered in each buffering hopper to 2, in this step, having unavoidably material jumps out buffering hopper 2 and stays and weigh on hopper suspension member 9, particularly the material of some fine particle shapes is more prone on the hopper suspension member 9 of weighing to pile up the material that allows LOAD CELLS 7 take for to weigh on hopper suspension member 9 also among calculating, and in fact the material of weighing on hopper suspension member 9 can not be packed together with material in the hopper 3 of weighing, the material of often only having packed and having weighed in hopper 3, thereby weighing result does not conform to the material of actual packing.

The utility model is because hopper suspension member 9 both sides of weighing are emptying aperture structure, less thereby material is difficult to pile up on the hopper suspension member 9 of weighing weighing precision impact.Stepper motor 4 is opened buffering hopper 2 material in bucket is delivered to and weighed in hopper 3, when involved hopper 3 blowings of weighing are when maybe in the hopper 3 of weighing, material is inadequate, material in buffering hopper 2 will flow into automatically weighs in hopper 3, material is in the hopper 3 of weighing, can produce pressure compression flexible member, thereby flexible member produces deformation, resistance strain gage be attached on flexible member the same with flexible member produce deformation and produce corresponding resistor change, by metering circuit, measure the variation of foil gauge resistance and be transformed to the electric signal output being in proportion with external force and draw weighing result.

The definition of bull scale

Bull scale carrys out word " Multihead Weighters " free translation and goes out from oceangoing ship.In China, be conventionally also called combination balance, electronics bull scale, assembly packaging scale etc.Engineering formal name used at school claims again " Selection and Constitute weighing apparatus ".It is comprised of the weighing unit of a plurality of independently charging discharging structures, and computer utilizes permutation and combination principle that the load capacity of weighing unit is carried out to automatic selection of optimal combination and calculates, and the weight combinations that draw the best, approaches target weight value is most packed.

The source of bull scale

The seventies in last century, Japanese agriculture association has proposed to relevant weighing apparatus enterprise the problem that green pepper weighs.In Japan, green pepper is normally sold in supermarket with the form of packed quantitative package, if every bag of green pepper quantitative values is 120g, true up 120g is a very difficult thing.Because single green pepper weight is heavier, and difference is larger, and dress has lacked and has been related to consumer's interests, has filled the cost that is related to enterprise more.Traditional mode is manual weighing, on a static electronic scale, weigh, a green pepper meets the 115g that is added to of a green pepper, rethinks that to look for green pepper that 5g is heavy to add up be almost impossible, the less green pepper of must taking away from 115g, then add a larger green pepper in addition.If weight substantially exceeds 120g or not enough 120g, also need repetition to work above, weigh like this efficiency extremely low, and be difficult to reach the result that approaches target weight (quantitative values).After technician investigates in a large number to this again, utilize combinatorial weighing principle successfully to solve above-mentioned green pepper and weigh problem.

The type of bull scale

As its name suggests, bull scale has a lot of " head ", and in fact namely " weighing bucket " counts type by the bucket that food packing industry is conventional now, is divided into 8 buckets, 10 buckets, 12 buckets, 14 buckets, 16 buckets, 20 buckets, 24 buckets etc.By environment for use type, be also divided into water proof type, rust-proof type, anti-collision type, universal etc., by packaging for foodstuff, daily use chemicals, tobacco, five metals (particle) industry adopts.By profile, be divided into double door, large column type, double skewed slots, low noise single open-door type.

The principle of work of bull scale

1, hoister feeds in raw material through loading plate, makes material focus on the main dish that shakes upper, then the vibration of being shaken and being coiled by master, makes material material is evenly distributed to line on the main dish that shakes and shakes in dish.

2, in loading plate, material does not have or by material level photoelectric detector, is measured not, just to mainboard, sends signal, then it is reinforced by mainboard, to hoister, to send feeding signal.

3, the line machine vibration that shakes, delivers to material in each buffering bucket by amplitude and the line feed time that shakes.

4, stepper motor work, opens buffering bucket the material in bucket is delivered in weighing bucket, and when involved weighing bucket blowing or when in weighing bucket, material is inadequate, the material in buffering bucket will flow in weighing bucket automatically.

5, material, in weighing bucket, produces weight signal by sensor, and process AD resume module becomes digital signal and by data bus, sends the mainboard of extra large river intelligent control device to.

6, the CPU on mainboard has read and has recorded the weight of each weighing bucket, then passes through to calculate, analyzes, combines, screens, and selects the combination weighing bucket that approaches target weight most, and sends the ready signal that combination balance has weighed up material preparation blowing.

7, when CPU receives the permission blowing signal that packaging machine sends, CPU just gives an order and starts driver drives stepper motor and open selected weighing bucket material is discharged to and in skewed slot, enters aggregate bin, if do not have aggregate bin just directly to enter packaging machine, and send the blowing signal of discharge to packaging machine.

8, after weighing bucket blowing, buffering bucket can be in time to weighing bucket feed supplement, weigh, combine, for blowing is next time prepared.

The principal feature of bull scale

1, the speed of weighing is fast---and 10 buckets can reach 70 bags/per minute, and 14 buckets can reach 120 bags/per minute.

2, dynamic weighing precision is accurate---and-± 0.1～2.0g。

3, automaticity is high----form one with hoister, packaging machine automatically to complete quantitative packaging system.

1 foreword

Combination balance claims again Selection and Constitute weighing apparatus, it is comprised of the weighing unit of a plurality of independently charging discharging structures, and computer utilization row combination principle combines and calculates the best, approaches most the weight combinations of target weight value and packs to the load capacity automatic selection of optimal of weighing unit.Sort scale and be and detect single product weight and whether conform to target setting, and by the packaging industry equipment of the sub-standard product of sorting unit automatic rejection.From practical standpoint, employing has the system-level single-chip microcomputer MSC1210 of 24 ∑-△ type A/D converters in conjunction with power cheaply solution and CAN SJA1000Controler and CAN bus transceiver 82C250, design a kind of 24 weighing data acquisition systems with CAN bus interface, can be applicable to combination weighing equipment, sorting equipment.

2 the Hardware Design

Fig. 1 is system hardware structure figure.System hardware adopts the direct pick-up transducers signal of system-level single-chip microcomputer MSC1210.The voltage input signal being produced by LOAD CELLS adopts difference input mode, by filtering circuit, directly received AIN0, the AIN1 of MSC1210, through the inner A/D conversion of MSC1210 image data, then image data is converted into CAN protocol data and transfers to CAN bus network, then by touch-screen deal with data.MSC1210 is built-in with temperature sensor, is convenient to late time data and proofreaies and correct, and gathers measures ambient temperature.

2.1 supply voltage

A/D translation data size only depends on input voltage V0 size, and A/D conversion accuracy depends on the stability of reference voltage V0.V0, VREF must get same power supply, and power-supply fluctuation is cancelled out each other, on the impact of A/D conversion nothing.The minimum driving voltage of this LOAD CELLS is 5V, and minimum exciting current is 25mA.The internal reference voltage that MSC1210 provides is not enough to driving sensor, therefore selects outside input reference voltage, closes internal reference voltage simultaneously and disturbs and power attenuation with noise decrease.

For these reasons, integrated cost is considered, selects low pressure difference linear voltage regulator LP2591 to provide 5V in order to stimulus sensor, is divided into 2.5V supplies with MSC1210 as the reference power source of A/D conversion by high precision resistance network.

LP2951 belongs to accurate low pressure difference linear voltage regulator, initial precision 0.5%, and voltage regulation factor and load regulation can reach 0.05%, have the features such as low quiescent current (≤8mA), low voltage difference, low-temperature coefficient (20 * 10-6/ ℃).Pressure reduction during underloading is 50mV; When it is 100mA load, pressure reduction is 380mV.Maximum output current is 100mA.

Each integrated resistance has parameter, performance, consistent feature affected by environment, and outer bound pair it disturb (as power source change, temperature variation) in intrinsic standoff ratio, to cancel out each other.The bleeder circuit of employing parallel resistance contributes to reduce temperature and floats, and improves stability.

2.2A/D converter

High-accuracy data acquisition core is the parameter index of A/D converter.It is range, effective resolution and switching time etc.

MSC1210 changes range to increase the dynamic range of input signal by programmable gain amplifier (PGA) and skew D/A converter (ODAC).MSC1210 changes range to adapt to different sensor input voltages by changing PGA own.If AIN0 is as homophase difference input channel, other any one passages all can be used as anti-phase difference input channel.Here select AIN0, AIN1 as the forward path of input pickup input voltage.The analog input of PGA is biased at most half of input range by ODAC, due to ODAC introduced simulation amount of bias but not digital quantity to PGA, so use ODAC can not reduce the performance of A/D converter.

The dynamic range of this system requirements input signal is 0～4000g, minimum input resolution is 0.1g, according to the linear input of A/D converter, output characteristics, A/D converter full scale voltage equates with ratio and the corresponding weight output ratio of differentiated minimum voltage simultaneously.System must guarantee that final measurement has the precision of 16.Other factors such as the drift of taking into account system supply voltage, temperature drift, therefore require A/D conversion at least should reach the actual converted precision of 18bit.Therefore, MSC1210 can meet requirement of system design.

2.3 temperature survey

MSC1210 built-in temperature sensor is convenient to late time data correction, gathers the temperature of measurement environment.Because its internal body diodes provides temperature sensing function, when all position of register is set is all 1 of input multiplexer, diode is just linked the input end of A/D converter, and all passages are opened.

The communication of 2.4CAN bus data

AD0～AD7 of SJA1000 is connected to the P0 port of MSC1210, and CS is connected to the pin P2_7 of MSC1210.P2_7 pin is 0 o'clock, and SJA1000 is chosen in CPU chip external memory address, and CPU carries out corresponding read/write operation by these addresses to SJA1000.The RD of SJA1000, WR, ALE are connected with the corresponding pin of MSC1210 respectively, and INT pin meets the INT0 of MSC1210, and MSC1210 can access SJA1000 by interrupt mode.

For strengthening the antijamming capability of CAN bus node, the TX0 of SJA1000 is connected with 82C250 by high speed photo coupling 6N137 with RX0, so just realizes the internodal electrical isolation of each CAN in bus.Adopt small-power power isolation module B05-05S that two power supplys of optocoupler part are isolated completely.Stability and the security of node by isolation, have been improved, as shown in Figure 2.

Sensor voltage output signal directly meets the AIN0 of MSC1210, AIN1 after after filtering; The reference voltage that the inner A/D of MSC1210 changes is LP2951, and output voltage obtains through precision resistance network dividing potential drop, as shown in Figure 3.

3 Design of System Software

Single-chip microcomputer gathers the data of A/D conversion and issues CAN network by CAN agreement, transmission data, the voltage data of the LOAD CELLS output that making software system receives and storage of collected arrives on touch-screen, the emphasis of software work comprises data calibration and data acquisition two parts.

3.1 data calibration

For reducing offset error and the gain error of device and system, need to adopt calibration steps.The skew of MSC1210 or whole system, gain error can reduce impact by correction.

CAL2～0 of calibration function ADCCON1 register (SFR DDH) is controlled each calibration process and is needed 7 tDATA cycles, and therefore, completing skew and gain calibration needs 14 rDATA cycles.After calibration completes, when interrupting allowing, can produce A/D conversion and interrupt.After correction completes, A/D converter interruption position is 1, represents to proofread and correct to finish to read valid data, and related program code is as follows:

ADCON1=0X01; // initialization gain and skew self calibration;

While (! (AISTAT & 0X20)); // wait down trigger.

3.2 data acquisition

Adopt Delta DOP human interface software ScreenEditor development platform, organized data collection and storage system, used CAN procotol and slave computer communication, carries out the Real-time Collection of weighing data, is specifically applied in weighing system collecting test system.

3.3 improve other measures that precision is taked

For guaranteeing to obtain a high-precision test macro, except using high-precision a/d converter, other modular design in system also have a great impact whole system precision.

(1) sensor is the core of whole system, obtain the mounting means that reliable data source will be noted resistance strain, and the floor installation face of sensor should be smooth, clean and tidy, without existence such as any oil film, glued membranes.Mounting seat requires the strength and stiffness higher than sensor itself.The installed surface of mounting seat will be adjusted level with level meter.During installation, common plain washer can not be adopted, spring washer should be used.To sensor, loading when stressed, load and loaded by force direction by sensor, avoiding laterally or additional torque power.

(2) digital device and analog device are independently-powered, and power supply is carried out to voltage stabilizing, and add filtering circuit, in order to avoid power supply noise exerts an influence to system.For preventing that conduction type high-frequency electromagnetic from disturbing, on sensor signal output terminal and power lead, add shielding pearl.When PCB layout, should by numerical portion and simulation part, divide isolation, digitally with isolation in analog as far as possible.

System can stable operation, and measurement result meets accuracy requirement, and display resolution is 1/40000.The data stabilization time is less than 1s.

4 conclusions

The weighing data acquisition scheme of this CAN bus is applicable to combination weighing or sorts under the environment of weighing the collection of load cell signal and storage, practice test through the environment of plant, proof system can long-time steady operation, there is good application prospect, also can be used in vehicle weighing system simultaneously.

Should be understood that, for those of ordinary skills, can be improved according to the above description or convert, and all these improvement and conversion all should belong to the protection domain of the utility model claims.

Claims (3)

1. a bull combination balance, comprises aluminium box, is positioned at the buffering hopper of placing in aluminium box outside from top to bottom and weighs hopper and two stepper motors that are positioned at that aluminium box inner side places from top to bottom and loading component; Loading component mainly comprises fixture under sensor upper fixing element, sensor, LOAD CELLS, sensor protection part, weigh hopper suspension member and metering circuit; it is characterized in that: described in the hopper suspension member of weighing by suspension member support plate one, suspension member support plate two and suspension member support plate three, formed; described suspension member support plate one, suspension member support plate two and suspension member support plate three adopt butt-joint integrally welded, the structure that described suspension member support plate one is emptied for both sides.

2. a kind of bull combination balance according to claim 1, it is characterized in that: under described LOAD CELLS front and back and sensor upper fixing element, sensor, fixture is bolted and is integral, wherein one end is fixed on aluminium box, and the other end is connected with the hopper suspension member of weighing.

3. a kind of bull combination balance according to claim 1, is characterized in that: described LOAD CELLS is resistance strain gage, and resistance strain gage is attached on flexible member, and metering circuit is connected with resistance strain gage.

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