Device for automatically weighing objects in conveyance

Abstract: A device for weighing slender or piece - like objects being conveyed - includes a driving means (300), a fixed stand (400), a movable stand (200), a conveyer (301A), and a weighing scale (500). As an object to be weighed is conveyed onto a supporting portion of the movable stand, the movable stand will be lowered thereby putting the object on the weighing scale and enabling the object to be separated from other mechanisms. After the object has been weighed, the movable stand will be restored to its original position and the object will continue to be conveyed. The weighing result can be input to a computer for analysis or control, or the device can be an integral part of a completely automatic operating system.

Description: The present invention relates to a device according to the preamble of claim 1. From DE-A-3432305 a device of the above-mentioned type is known. The conveying surface of this known device (refer to figures 6-8) is formed by several small coplanar belts each passing between two coplanar parallel adjacent small strips of a plurality of strips forming the weighing surface. The belts can be moved above and below the weighing surface such that objects can either be carried by the belts to be conveyed or carried by the weighing surface to be weighed. Thus, in the device known, the objects being conveyed are located freely. This is inconvenient to e.g. light-weight articles such as mail items. Such items will vibrate up and down on the conveyer and can shift over the conveyor. Accordingly, this known device can not provide an accurate location for the object on the conveyor, which can lead to e.g. congestion of items. There is also a risk of objects being lost from the conveyor by falling down. The object of the present invention is improving weighing of articles. Therefore, a weighing device according to the preamble of the description is characterised by the features of the characterizing part of the annexed main claim. According to the present invention, it is important that wedging is only effective during conveyance of the objects, while during the weighing no wedging action may be present, since this would effect the weighing results. Therefore, according to the invention driven rollers oppose the vertically displaceable portion such that an object is wedged in the upper position of the vertically displaceable portion. Furthermore, use of driven rollers opposing the vertically displaceable portion allows for a simple design since those driven rollers can be given a fixed position, such that simple connection means to the drive source can be used and the suspension of those driven rollers need no special design. The device according to the invention allows for reliable positioning of the object, enhancing the weighing operation and decreasing the amount of errors. In combination with the features of the annexed claim 3, the drive power needed for the driven rollers can be conveniently reduced. Further objectives and advantages of the present invention will become apparent to those having skill in the art in view of the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of one embodiment of a device for automatically weighing objects being conveyed in accordance with the present invention; Fig. 2 is a side view of the device of Fig. 1 in accordance with the present invention, showing an object to be weighed at an initial position; Fig. 3 is a side view of the device of Fig. 1, showing the object to be weighed being conveyed to a weighing position; Fig. 4 is a side view of the device of Fig. 1, showing the object being weighed by a weighing scale; Fig. 5 shows the object being further conveyed after having been weighed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, one embodiment of a conveying device 23 for automatically weighing objects in conveyance according to the present invention is illustrated. As shown in Fig. 1, the device 23 of the present invention comprises a driving means 300, for example a motor, a first conveying means 301A and a first idle wheel 310 thereof, a second conveying means 301B and a respective second idle wheel 201A, a third conveying means 301C and a respective third idle wheel 201B, a fixed stand 400 (Fig. 2), a movable stand 200 with a pair of rocking arms 120 and a weighing scale 500 located under the movable stand 200, and sensing means S1, S2. A novel aspect of the present invention is the movable stand 200 that includes a supporting stand with a square opening 208 in the middle portion thereof. At both ends of the opening 208 there are disposed the second and third idle wheels 201A and 201B that are in cooperative relationship with the second and third conveying means 301B and 301C respectively to convey an object 10 to be weighed. Referring to Fig. 2, a movable end 122 of each of a pair of rocking arms 120 is pivotally connected at each end of the movable estand 200. The other end of each rocking arm 120 is pivotally connected at a pivot 101. A pair of electromagnetic actuators 100, such as a solenoid, is connected to the middle portion of the rocking arm 120 nearer the starting position of this device. When the electromagnetic actuator 100 is activated, the movable end 122 is pulled down with the pivot 101 as a fulcrum. Since the moving stand 200 is attached to the movable ends 122 of both of the rocking arms 120, both movable ends 122 are actuated and descend simultaneously to move stand 200 to a lower horizontal plane. As best shown in Fig. 4, the second and third idle wheels 201A and 201B are connected to move with the movable stand 200 in vertical planes corresponding with the second and third conveying means 301B and 301C, respectively. The first conveying means 301A precedes the second conveying means 301B in the conveying device 23. The driving means 300, e.g. a stepping motor, drives the first, second and third conveying means. The first conveying means 301A is urged by a first belt wheel 302 (Fig. 1) and a first conveying belt 303 thereof. Referring again to Fig. 1, the second and third conveying means 301B, 301C are urged by second belt wheels 304, a second conveying belt 305, third belt wheels 306, and a third conveying belt 307. Disposed beneath the opening 208 of the movable stand 200 is a weighing scale 500. A weighing plate 501 of the weighing scale 500 is positioned above the main body of the weighing scale with its surface a little lower than the movable stand 200 so that the weighing plate 501 does not obstruct the conveyance of the article to be weighed. The operation of the apparatus of the present invention can best be understood by referring to Figs. 2 through 5. Prior to reaching the first conveying means 301A and first idle wheel means 310, object 10 comes in contact with a first sensor S1, such as photo-sensor, and the driving means 300 is actuated to convey object 10 to a position to be weighed, as shown in Figs. 2 (initial position) and 3 (weighing position). At the positions shown in Figs. 2 and 3, the electromagnetic actuator 100 is not activated. Therefore, the movable ends 122 of the rocking arms 120, due to the force of the springs 104, urge the second and third idle wheels 201A, 201B upward and in close contact with the second and third conveying means 301B, 301C, whereby the object 10 can be delivered onto the movable stand 200 as shown in Fig. 3. In the non-weighing state, the second sensor S2 (e.g. a photo-sensor) is deactivated, with an activating piece S21 of the second sensor S2 disposed behind the third conveying means 301C isolating the second sensor S2 and inhibiting the generation of a sensor signal. When the object 10 reaches the activating piece S21, it raises the activating piece S21 upward and enables the second sensor S2 to send a sensor signal to actuator 100. The electromagnetic actuator 100 is thereby activated and the movable end 122 of the related rocking arm 120 is pulled down lowering movable stand 200 and the movable end of the other rocking arm. The object 10 to be weighed is then seated on the weighing plate 501 of the weighing scale 500, as illustrated in Fig. 4. The weighing scale can weigh the object 10, and display the result on the display means of the weighing device 500 or send out a signal to perform some other control functions. In this manner, an accurate weight of the object 10 can be readily obtained as the object to be weighed is isolated from the rest of the device. After a pre-set time period following measurement of the object's weight, the electromagnetic actuator 100 will be deactivated, and both rocking arms 120 are drawn back by the force of the springs 104 and the movable stand 200 is restored to its initial position. The object 10, having been weighed, is again held between the second and third idle wheels 201A, 201B and the second and third conveying means 301B, 301C, and thus continues to be conveyed as shown in Fig. 5. It is to be understood that said rocking arm 120 can also be substituted by a equivalent means, such as cam or crank means driven by a motor and obtained the same function function as mentioned above. It should be emphasized that by using this invention the slender piece - like article is weighed automatically in a moving conveyer and the result can be trasmitted to a computer for analysis or control. Thus, the automatic weighing device of the present invention can play an important role in a completely automatic operating system. As various embodiments of the invention may be made without departing from the invention as claimed, it is to be understood that the specific embodiments described herein or shown in the accompanying drawings are to be interpreted as illustrative and not in a limiting sense.

Claims: Device for weighing objects during the conveyance of said objects comprising: means for conveying an object (10) to a weighing location; means (S2, S21) for sensing said object's location at said weighing position; said conveying means including a vertically displaceable portion equipped with an actuating means (100, 120, 104), which is actuated in response to said sensing means (S2, S21) for moving said object from a first horizontal position to a second lower horizontal weighing position; means (500) for weighing said object (10) in said second lower horizontal weighing position; characterized in that the conveying means comprises driven rollers (301b, 301c) opposing the vertically displaceable portion to wedge the object between the portion and the driven rollers in the first horizontal position. Device according to claim 1, characterized in that the means for weighing said object comprises a weighing surface formed by a single plate (501); said vertically displaceable portion comprising a plate (200) running parallel to the weighing surface, said plate having an opening (208) being registered with and shaped congruent to and dimensioned larger then the weighing surface such that said weighing surface can pass with play. Device according to claim 1 or 2, characterized in that the vertically displaceable portion comprises idle rollers (201a, 201b) opposing said driven rollers (301b, 301c).

Inventors: WU SHENG-JUNG, WU, SHENG-JUNG
Applicants: WU SHENG JUNG, WU, SHENG-JUNG
Application year: 1988
Main classification: G01G19
IPC codes: G01G11, G01G19