JPH038494B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a load cell scale.

Generally, load cell scales perform weighing by transmitting the load placed on a plate to the load cell, and the load cell outputs an electrical signal according to the load at that time, but it detects the accurate output according to the received load. In order to do this, conventionally, a rigid base is provided at the bottom of a case that houses the components, and a fixed part of the load cell is fixed to this base. Furthermore, in order to protect the load cell from uneven loads, a stopper is provided on the base to limit horizontal movement of the load cell. Therefore, the number of parts increases, the base in particular is heavy, and the cost increases.

This invention was made in view of these points, and aims to provide a load cell scale that is lightweight by omitting the base and that can protect the load cell from uneven loads with a simple structure. .

This invention fixes the load cell by using the inner surface of the cover that covers the top surface of the case that houses the components of the load cell scale, thereby omitting the base from the bottom of the case and attaching the mounting plate connected to the load cell to the case. The cover is provided with a stopper that faces the upper surface of the cover and faces the periphery of the plate, so that when an uneven load is applied to the plate, the stopper restricts the horizontal movement of the plate, and It is possible to protect the load cell from unbalanced loads by transmitting the load in the vertical direction to the load cell, simplifying the structure for protecting the unbalanced loads, and since the stopper is formed all around the periphery of the mounting plate, The stopper portion is strong and stable, and can be sufficiently protected from uneven loads without adding any parts to the tray side or changing its shape.

An embodiment of the present invention will be described based on the drawings.
Reference numeral 1 denotes a case, and three or four legs 2 are screwed onto the bottom surface of the case 1 so as to be adjustable in height, and an opening on the top surface of the case 1 is closed by a cover 3 made of plastic. A metal fitting 4 is inserted into a part of the lower surface of this cover 3, and a fixing portion 6 of a load cell 5 is screwed to this metal fitting 4. When the cover 3 is made of a metal material, the metal fitting 4 may be omitted and the load cell 5 may be directly fixed. A center portion of a plate support frame 9 made of an elastic metal plate such as aluminum is screwed to the pressure receiving portion 7 of the load cell 5 with a spacer 8 interposed therebetween. A stopper 11 is formed on the upper central surface of the cover 3 and faces the lower central surface of the mounting tray 10 at a predetermined distance. Even on the entire surface other than the stopper 11, the distance between the cover 3 and the mounting plate 10 is small,
A bank-shaped stopper 12 is also formed around the cover 3 and faces the periphery of the mounting plate 10 with a slight interval therebetween. The tray 10 is made of elastic plastic, and bosses 13 erected at the four corners of its lower surface penetrate the cover 3 and are detachably connected to the tray support frame 9.

Next, a transformer 14 is held in a suspended state on the cover 3, and a power supply section (not shown), a display section 15, a switch 16, an AD converter (not shown), etc. are connected to and controlled by the transformer 14. A CPU (not shown) and the like are held on the PW board 17. This PW board 17 is held on the inner surface of the cover 3. Further, a level 18 is attached to the mounting plate 10 to check the levelness when adjusting the height of the leg 2.

Furthermore, the load cell 5 has a thin strain-generating portion 1.
A strain cage forming a bridge circuit is fixed at points 9 and 20, and a cylindrical spacer 21 is interposed on the side of the load cell 5 to connect the PW plate 2.
3 is attached with screws 22. This PW
The plate 23 is also held by a guide 24 formed in the case 1. This PW board 23 is equipped with an amplifier or the like for amplifying the output of the bridge circuit. Further, a display window 25 is formed in the cover 3 and faces a display device held by the PW board 17.

In such a configuration, when an object is placed on the tray 10, the load is transmitted from the tray support frame 9 to the pressure receiving part 7 of the load cell 5, and the load cell 5 generates an electric signal according to the load by deforming the strain generating parts 19 and 20. Output.

The main parts constituting the load cell scale are the load cell 5, the transformer 14, the power supply section,
Although the CPU, AD converter, etc. are housed in the case 1, since they are held by the cover 3 that closes the top opening of the case 1, there is no need to provide a sturdy base at the bottom of the case 1. Therefore, the number of parts can be reduced, the weight can be reduced, and costs can be reduced.

Further, when an overload is applied to the placing plate 10, the stopper 11 of the cover 3 supports the placing plate 10. When an object is placed near the end of the tray 10, the tray 10 is elastically deformed and supported by the upper surface of the end of the cover 3. Therefore, it is possible to protect the load cell 5 from overload. In this case, by setting the elasticity, amount of deflection, etc. of the loading tray 10 and tray support frame 9 at the time of design according to the capacity of the load cell scale, there is no need to adjust the stopper mechanism to protect the load cell 5 from overload. Become. Further, since the mounting tray 10 is surrounded by a bank-like stopper 12 formed on the cover 3 with a slight gap, movement of the mounting tray 10 and the tray support frame 9 in the plane direction can also be restricted. It is possible. That is, it is possible to prevent an unbalanced load on the mounting tray 10 and to transmit the load as a force in the vertical direction to the pressure receiving part 7 of the load cell 5 to perform accurate measurement. Further, since the cover 3 can be assembled into a unit by assembling the parts in a wide space with the inner surface of the cover 3 facing upward, and then the cover 3 can be connected to the case 1, assembly is extremely easy.

Since the present invention is configured as described above, the load cell can be attached to the cover covering the top surface of the case, and the sturdy base from the bottom of the case can be omitted.
This reduces the weight and restricts the horizontal movement of the mounting plate with a simple structure in which a stopper facing the periphery of the mounting plate connected to the load cell is provided on the cover facing the bottom surface of the mounting plate. As a result, it is possible to correct the unbalanced load to a vertical load and transmit it to the load cell to perform accurate weighing and protect the load cell from the unbalanced load.Moreover, the stopper can be applied all the way around the periphery of the plate. Because of this, the strength of the stopper part is high and stable, and it can be sufficiently protected from uneven loads without adding any parts to the mounting plate or changing its shape. It has the effect of

[Brief explanation of the drawing]

The drawings show one embodiment of the invention.
The figure is a plan view, FIG. 2 is a vertical front view, FIG. 3 is a vertical side view, and FIG. 4 is a partially exploded perspective view. 1... Case, 3... Cover, 5... Load cell, 6... Fixed part, 10... Place plate, 12... Stopper.

Claims (1)

[Claims] 1. A cover that closes the top surface of the case is provided, a mounting plate is arranged opposite to the top surface of the cover, a fixing part of a load cell that receives the load from the mounting plate is fixed to the bottom surface of the cover, and the load cell is fixed to the bottom surface of the cover. A load cell weigher characterized in that bank-like stoppers are formed on the entire periphery of the mounting plate and face each other with a slight gap in the horizontal direction.