Weigh-in-motion scale

• US 4,957,178 A
• Filed: 08/22/1989
• Issued: 09/18/1990
• Est. Priority Date: 08/22/1989
• Status: Expired due to Fees

• Current Assignee: Mettler-Toledo Incorporated (Mettler-Toledo International Inc.)
• Original Assignee: Toledo Scale Corp. (Mettler-Toledo LLC)
• Inventors: Mills, Nigel G.
• Primary Examiner(s): Miller, Jr., George H.
• Application Number:
  US07/397,108
• Time in Patent Office: 392 Days
• Field of Search: 177/154, 177/255, 177/134, 177/135
• US Class Current: 177/134
• CPC Class Codes: G01G 19/024 using electrical weight-sensitive devices

Abstract

Apparatus for weighing vehicles in motion includes a base to be anchored to a roadbed below ground level in the path of moving vehicles and a pair of scale platforms mounted on the base for receiving the wheels on the opposite sides of the moving vehicles. Load cells are provided between the base and the platform for producing signals indicating the load applied by each wheel on the platform. A pair of flexure struts is connected between each platform and the base to apply a preload and permit relative movement therebetween in the vertical direction and to resist relative movement in the horizontal direction. The flexure struts extend lengthwise in the direction of traffic flow and are resistant to loads in that direction while being flexible in the vertical direction to permit application of the preload and flexing of the load cells. The dynamic weight signals from the load cells are converted to digital form and operated on to provide information as to the weights of the passing vehicles.

Claims

1. Apparatus for weighing vehicles in motion comprising a base for anchoring to a roadbed in the path of moving vehicles, a weighing platform mounted on said base for receiving the wheels of moving vehicles, load cell means between the base and the platform for providing signals indicating the loads applied by the wheels on the platform, and means connected between the platform and the base to apply a vertical preload and to resist relative horizontal movement between the base and the platform.

2. Apparatus as claimed in claim 1 wherein said preload means includes a flexure arm extending lengthwise between the platform and the base, said arm resisting relative horizontal movement between the platform and the base and flexing to permit relative vertical movement therebetween, and means connecting said arm to apply a vertical preload between the platform and base.

3. Apparatus as claimed in claim 2 including means for setting said vertical preload to a predetermined amount.

4. Apparatus as claimed in claim 2 including a second flexure arm extending lengthwise between the platform and the base.

5. Apparatus as claimed in claim 1 wherein said preload means is connected between the platform and the base parallel to the direction of traffic flow, and including means for flexing said flexure means to apply a downward preload to said platform.

6. Apparatus as claimed in claim 5 including means for flexing said preload means a predetermined amount to apply a predetermined preload between said platform and base.

7. Apparatus as claimed in claim 5 wherein said preload means is connected between the vehicle exit end of the weighing platform and the vehicle exit end of the base, whereby vehicle deceleration over said platform tends to compress the preload means.

8. Apparatus for weighing vehicles comprising a base for anchoring to a roadbed, a scale platform mounted on the base for receiving the wheels of vehicles, load cell means between the base and the platform for providing signals indicating the load applied by the wheels on the platform, at least one flexure strut connected lengthwise between the platform and the base parallel to the direction of vehicle movement onto and off of said platform, said strut having a length greater than its thickness so as to be resistant to loads applied along its length and relatively flexible to loads applied transverse to its length, and means for using said flexure strut to vertically preload said platform.

9. Apparatus as claimed in claim 8 including means for flexing the flexure strut to apply a predetermined preload on said platform.

10. In a vehicle scale including a base to be installed in a roadbed, a weighing platform mounted on said base to receive a vehicle wheel, and load cell means between the weighing platform and the base to produce a signal indicative of the load applied by the wheel on the platform, a method of connecting the weighing platform to the base comprising the steps of connecting a strut to extend lengthwise between the platform and the base in the direction of vehicle movement on to and off the platform, said strut being resistant to forces applied along its length and relatively flexible to forces applied transverse to its length, whereby said strut resists relative horizontal movement between the platform and the base and permits relative vertical movement therebetween, and using the strut to vertically preload the platform.

11. A method as claimed in claim 10 including the step of flexing the strut a predetermined amount to apply a predetermined preload on the platform.

12. A method as claimed in claim 10 including the step of flexing the strut to preload the platform.