JPH0139535B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a weighing conveyor, and particularly to a weighing conveyor capable of correcting a dynamic weighing value to a static weighing value. Generally, a weighing conveyor weighs an article while it is being conveyed, so the measured value (dynamic weight value) differs from the weight value measured with the object being weighed stationary (static weight value). Yes, it is necessary to correct dynamic measurement values to static measurement values. Therefore, for example, in a weighing conveyor using a belt conveyor, an object whose static weight value is known in advance is conveyed on the belt conveyor multiple times, the average value of the dynamic weight values is determined, and this average value and the static weight value are calculated. A correction constant, which is the deviation from the weighed value or the ratio between the two, has been determined and used to correct the dynamic weighing value of an article to be weighed whose weight is unknown to the static weighing value. In the case of a belt conveyor, the weight of each part of the belt is almost uniform no matter which part of the belt conveys the article to be weighed, so the above correction can be made. There are variations in weight, and as mentioned above, no matter where the weight is being transported, it is not possible to accurately correct it to a static weighing value by using a constant correction value. Further, when a carrier is provided in the chain to facilitate the transportation of the article to be weighed, it becomes increasingly difficult to correct the static weight value due to the influence of variations in the weight of each carrier and the mounting condition. This invention was made in order to solve the above problem, and a chain is provided with a plurality of carriers along its conveying direction, and a correction is made for each carrier to correct a dynamic weighing value to a static weighing value. Set a constant,
Each time each carrier reaches the load detector, the dynamic measurement value at that time is corrected to a static measurement value using a correction constant, sign, or ratio corresponding to the carrier that has arrived. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on an illustrated embodiment in which the present invention is implemented in a high-speed weighing conveyor. The high-speed weighing conveyor implementing this invention has two weighing conveyors 1 and 2 in order to increase the number of pieces weighed per unit time, and the weighing conveyor 1 has two chains 3a and 3b stretched in parallel. , a weighing platform 4 and a load detector 5 are placed at appropriate locations on the tensioning path. The weighing conveyor 2 has two chains 6.
a, 6b are stretched outside the chains 3a, 3b, and the weighing platform 7 and load detector 8 are placed a little apart from the weighing platform 4 and load detector 5. Carriers 9a to 9d are provided between the chains 3a and 3b at appropriate intervals as shown in FIG. to 1
0d is provided, and these chains 3a, 3
b, 6a, and 6b are caused to travel synchronously by the yawter 12. Therefore, since the article to be weighed conveyed by the chains 3a and 3b passes the weighing platform 4, the article conveyed by the chains 6a and 6b passes the weighing platform 7, so that the unit time is This allows you to increase the number of pieces weighed per hit. A rotation detection disk 14 is attached to the motor 12, as shown in FIG. This rotation detection disk 14 cooperates with an optical detector 15 to generate a detection pulse each time the carriers 9a to 9d follow the weighbridge 4 and each time the carriers 10a to 10d pass the weighbridge 7. Yoni Slit 1
6 is formed. The detected pulse is shown in Figure 4d. In the figure, 18a indicates that the carrier 9a is
8b is carrier 9b, 18c is carrier 9c
However, 18d is a detection pulse generated when the carrier 9d passes over the weighbridge 4, 20a is a detection pulse generated by the carrier 10a, 20b is a detection pulse generated by the carrier 10b,
c is carrier 10c, 20d is carrier 10d
This is a detection pulse generated when passing over the weighing platform 7. Further, the rotation detection disk 14 is formed with a slit 25 so as to cooperate with the optical detector 22 to generate a reset pulse 24 when the carrier 10a passes over the weighing platform 4. The reset pulse 24 is shown in FIG. 4a. Since this reset pulse 24 is supplied to the clear terminal of the J.K flip-flop 26, the Q output becomes "0" and the output becomes "1" as shown in FIGS. 4c and 4d. The reset pulse 24 is also supplied to preset counters 28 and 30, and the counter 28 is set to "1" and the counter 30 is set to "4". Detection pulses 18a to 18d, 20a to 2
Since 0d is supplied to the T terminal of the J/K flip-flop 26, its Q and output are as shown in Fig. 4c,
After the reset pulse 24 is supplied as shown in d, the detection pulses 18a to 18d, 20a to 2
It is inverted every time 0d is supplied. The detection pulses 18a to 18d, 20a to 20d are supplied to counters 28 and 30 via AND gates 32 and 34, which are opened and closed by this Q output.
The count values of the counters 28 and 30 change as shown in the table below.

[Table] Therefore, by determining the count value of the counter 28 when the Q output of the J.K flip-flop 26 is "1", it is possible to determine which of the carriers 9a to 9d is on the weighing platform 4,・K flip 2
By determining the count value of the counter 30 when the output of the counter 6 is "1", it is possible to determine which of the carriers 10a to 10d is on the weighing platform 7.
The circuits for this purpose are logic discrimination circuits 35 and 36. The discrimination logic circuit 35 outputs an output line a when the carrier 9a is on the weighing platform 4, an output line b when the carrier 9b is on the weighing platform 4, and an output line c when the carrier 9c is on the weighing platform 4. To, Carrier 9d
is on the weighing platform 4, the output line d is configured to generate an output "1". Further, the determination logic circuit 36 determines that the carrier 10a is the weighing platform 7.
When the carrier 10d is on the weighing platform 7, an output "1" is generated on the output line e and on the output line h when the carrier 10d is on the weighing platform 7. Since these circuits can be easily constructed using an AND circuit and an inverter, detailed explanation thereof will be omitted. Using the outputs of the discrimination logic circuits 35 and 36, static correction value calculation and storage circuits 37 and 42 correct the static measurement value. Since both weighing conveyors 1 and 2 are similarly corrected by these circuits, only the circuit 37 for weighing conveyor 1 will be described. 38a to 38d are correction value registers, 38a stores a correction constant and a sign for the carrier 9a, . . . 38b stores a correction constant and a sign for the carrier 9b, respectively. A device for this storage will be described later. When the carrier 9a transports the article to be weighed and reaches the load detector 5, an output "1" is generated on the output line a of the discrimination logic circuit 35, and is supplied to the AND gate 40a. As a result, the correction constant and sign for the carrier 9a stored in the correction value register 38a are supplied to the adder/subtractor 46. The adder/subtractor 46 is supplied with the output of the load detector 5 (dynamic analog weighing signal of the article being weighed carried by the carrier 9a) converted into a dynamic digital weighing signal by the A/D converter 44. , an adder/subtractor 46 adds or subtracts a correction constant from the dynamic digital measurement signal according to the sign, thereby correcting the dynamic digital measurement signal to a static digital measurement signal. Similarly, each time an output "1" occurs on the output lines b to d of the discrimination logic circuit 35, the static digital signal is Corrections are made to the weighing signal. The correction constants and codes are stored in the correction value registers 38a to 38d as follows. First, close the switch 48, and send the correction start signal from the correction start signal generator 50 to the AND gates 52a to 52d.
supply to. And each carrier 9a to 9d,
Master pieces having approximately the same static weight are placed on 10d to 10d and transported. In addition to the correction start signal, the AND gate 52a is supplied with the output of the output line a of the discrimination logic circuit 35 and the digital measurement signal of the A/D converter 44, so the output of the AND gate 52 is supplied with the cumulative In a register 54a, the dynamic digital weighing signal of the master piece on the carrier 9a is accumulated each time the carrier 9a reaches the load detector 5. Furthermore, every time an output is generated on the output line a of the discrimination logic circuit 35, a detection pulse is sent to the counter 58a via the AND gate 56a.
is counted. This count value is carrier 9
a represents the number of times a has reached the load detector 5. When this count value reaches a predetermined value, this counter 58a generates an output, and the divider 60a responds to this output to cause the accumulation register 54 to
The average value of the dynamic digital measurement signal is calculated by dividing the cumulative value of a by a predetermined value set in a setting device (not shown). This average value is subtracted by the subtractor 62a from the static digital measurement value of the master piece stored in the static measurement value storage 64a using a numeric keypad or the like, and the subtracted value and sign are used as a correction constant and sign in the correction value register 38a. is memorized. Other correction value registers 38b to 38d
The correction constant and sign are stored in the same manner. Note that 66 is an A/D that converts the dynamic analog weighing signal of the load detector 8 into a dynamic digital weighing signal.
A converter 68 converts this dynamic digital weighing signal into a carrier 1 in the static correction value calculation and storage circuit 42.
This is an adder/subtractor for adding and subtracting correction constants of correction value registers (not shown) corresponding to 0a to 10d. The corrections in the adders and subtracters 46 and 68 are performed alternately because the discrimination logic circuits 35 and 36 alternately produce outputs. Further, static correction value calculation and storage of correction constants in storage circuits 37 and 42 are performed in parallel. This invention provides a chain with a plurality of carriers,
It detects which of these carriers has reached the load detector, and corrects the dynamic weight value at that time to a static weight value using a correction constant, sign, or ratio depending on the carrier. Therefore, even if there is variation in the weight of the chain, variation in the weight of the carrier, or even if the mounting state of the carrier is varied, the static measurement value can be accurately corrected. Therefore, there is no need to take into consideration the constant weight of the chain or carrier during production, and there is no need to consider the mounting state of the carrier, which improves the productivity of the weighing conveyor. In the above embodiment, two weighing conveyors are installed in parallel, but only one weighing conveyor or three or more weighing conveyors may be installed in parallel. Further, the number of carriers can be increased or decreased depending on usage conditions. Although the deviation between the average value of the static metric value and the dynamic metric value was used as the correction constant, the ratio of the average value of the dynamic metric value to the static metric value may also be used. In that case, a divider must be used in place of the subtracters 62a to 62d, and a multiplier must be used in place of the adder/subtractor 46. A slit 25 and an optical detector 22 are used to generate the reset pulse 24, but if one of the slits 16 has a different width or another slit is added close to one of the slits 16, The slit 25 and optical detector 22 are not necessary. Instead of the detection circuit disc 14, a light shield may be provided on the carrier, and an optical detector may be provided on the side of the conveyor. Furthermore, a magnetic detector may be used instead of the optical detector.

[Brief explanation of drawings]

FIG. 1 is a plan view of a high-speed weighing conveyor embodying the present invention, FIG. 2 is a front view thereof, FIG. 3 is a block diagram thereof, and FIG. 4 is a timing chart thereof. 3a, 3b, 6a, 6b... Chain, 5, 8... Load detector, 15, 16... Detection pulse generation circuit, 2
2, 25... Count start signal, 28, 30... Counter, 35, 36... Discrimination logic circuit, 38a to 3
8d... Correction value register, 46, 68... Addition/subtraction unit (operation unit).

Claims (1)

[Claims] 1. At least two chains arranged parallel to each other at intervals and fed in a predetermined direction, and a plurality of chains arranged along the length of these chains, each of which straddles between the chains. a load detector which is provided at a predetermined position on the conveying path of the chain and applies the load of each carrier that has reached the predetermined position each time the carrier reaches the predetermined position; a circuit that generates a detection pulse each time each of the carriers reaches the load detector; a circuit that generates a count start signal each time a predetermined one of the carriers reaches the load detector; a first counter that counts the detection pulses after generation of the count start signal; and a discrimination logic that generates a discrimination signal representing the carrier that has reached the load detector based on the count value of the first counter. The output of the load detector corresponds to the discrimination signal generated by the discrimination logic circuit when a predetermined article is placed on each carrier. and a plurality of accumulation registers for accumulating the signals, and each time the discrimination logic circuit provided corresponding to each of the carriers generates the corresponding discrimination signal, the detection pulses generated at that time are counted, and the count value is a predetermined value. a plurality of second counters each of which generates a computation command signal when the computation command signal reaches a value; and a plurality of second counters provided for each of the cumulative registers, which divides the cumulative value of the corresponding cumulative register by the predetermined value in response to the computation command signal. a plurality of dividers provided for each of these dividers, and a subtractor provided for each of these dividers to calculate the deviation and sign between the division value of the corresponding divider and the measured value of the article in a resting state; and a plurality of correction value registers for storing the outputs of corresponding subtractors, and a plurality of correction value registers provided corresponding to these correction value registers, and the above-mentioned discrimination generated by the discrimination logic circuit when an arbitrary article is placed on each of the carriers. A plurality of gate circuits select a corresponding value stored in the correction value register based on the signal, and perform addition/subtraction between the selected value stored in the correction value register and the output of the load detector at that time. A weighing conveyor comprising an adder/subtractor. 2. At least two chains arranged parallel to each other at intervals and feeding in a predetermined direction, and a plurality of chains arranged along the length of these chains, each of which is installed in a state spanning between the chains, and carries an article. a carrier to be placed; a load detector which is installed at a predetermined position on the conveyance path of the chain and applies the load of the carrier each time the carrier reaches the predetermined position; A circuit that generates a detection pulse each time the carrier reaches the load detector, a circuit that generates a count start signal every time a predetermined one of the above carriers reaches the load detector, and a circuit that generates a count start signal every time a predetermined one of the carriers reaches the load detector, and after the count start signal is generated, a first counter that counts the detection pulses; a discrimination logic circuit that generates a discrimination signal representing the carrier that has reached the load detector based on the count value of the first counter; a plurality of cumulative outputs of the load detectors, each of which is provided correspondingly to each carrier, and which corresponds to the discrimination signal generated by the discrimination logic circuit when a predetermined article is placed on each of the carriers; Each time the register and the discrimination logic circuit provided corresponding to each of the carriers generate the corresponding discrimination signal, the detection pulses generated at that time are counted, and when the count value reaches a predetermined value, the calculation is performed. a plurality of second counters each generating a command signal; and a plurality of dividers provided for each of the cumulative registers and dividing the cumulative value of the corresponding cumulative register by the predetermined value in response to the calculation command signal. , a divider provided for each of these dividers to calculate the ratio of the division value of the corresponding divider to the measured value of the article in a resting state, and a divider provided corresponding to each of these dividers to store the output of the corresponding divider. A plurality of correction value registers are provided corresponding to these correction value registers, and the above-mentioned discrimination logic circuit corresponds to the discrimination signal generated by the discrimination logic circuit when an arbitrary article is placed on each of the carriers. A weighing conveyor comprising: a plurality of gate circuits that select a value stored in a correction value register; and a multiplier that multiplies the selected value stored in the correction value register by the output of the load detector at that time.