Mobile working machine provided with stability monitoring

• US 20040119597A1
• Filed: 08/28/2003
• Published: 06/24/2004
• Est. Priority Date: 03/02/2001
• Status: Active Grant

• Current Assignee: Putzmeister Engineering GmbH
• Original Assignee: Putzmeister Aktiengesellschaft
• Inventors: Petzold, Wolf-Michael, Gelies, Stephan, Alwes, Dieter
• Granted Patent: US 7,012,540 B2
• Time in Patent Office: Days
• US Class Current: 340/679
• CPC Class Codes: B66C 23/78 Supports, e.g. outriggers, for mobile cranes
• CPC Class Codes: B66C 23/80 hydraulically actuated
• CPC Class Codes: B66C 23/90 Devices for indicating or limiting lifting moment
• CPC Class Codes: B66C 23/905 electrical
• CPC Class Codes: E02F 9/085 Ground-engaging fitting for supporting the machines while working, e.g. outriggers, legs for vehicles in general B60S9/00, for cranes B66C23/78
• CPC Class Codes: E04G 21/0436 on a mobile support, e.g. truck
• CPC Class Codes: G01L 5/0071 Specific indicating arrangements, e.g. of overload

Abstract

The invention relates to a mobile working machine, particularly a mobile concrete pump, comprising a device for monitoring the stability thereof when in operation. The working machine comprises a chassis (10), which contains a supporting structure with two front and two rear support struts (20). The support struts can be extended out of a transporting position and into at least one supporting position and each can be supported on a surface (28) by a telescopic supporting jack or foot (26). The working machine additionally comprises a working boom (14), which can be extended out of a transporting position and into working positions that project beyond the chassis, which can rotate about a vertical axis that is fixed with regard to the chassis, and which is preferably provided in the form of a concrete distributing boom. Measuring devices for determining the respective supporting load are arranged in the area of the supporting foot and their output signals are sent to a stability monitoring device. According to the invention, at least one force sensor (32, 34) is arranged in each supporting jack and is connected in an electrical measuring circuit (36, 38) for outputting a supporting load dependent measurement signal. The monitoring device comprises an evaluation electronic unit (54) which, in predetermined sampling cycles, can be subjected to supporting load measured values and, for their comparison, can be subjected to at least one predetermined stability-determining threshold value.

Claims

1. Mobile work device, in particular mobile concrete pump, which a vehicle chassis (10), with two forward and two rearward support struts (20) extendable from a transport position to at least one support position and with respectively one preferably telescopic support foot (26) supportable upon the ground (28), with a work boom (14), preferably a concrete distribution boom, extendable from a driving position to a work position projecting beyond the vehicle chassis and rotatable about a vehicle chassis-fixed vertical axis (13), with a measurement device (30) provided in the area of the support feet (26) for determining the respective support loads and with a support stability monitoring device evaluating or responding to the output signals of the measurement assemblies, thereby characterized, that at least one force sensor (32, 34) is provided for each support foot (26), that each force sensor is provided in an electrical measurement circuit (36, 38) for output of a support load dependent measurement signal and that the monitoring device includes an evaluation electronic (54), which in predetermined sampling cycles evaluates support foot derived support load measurement values for comparison with at least one predetermined stability determining threshold value.

2. Work device according to claim 1, thereby characterized, that the evaluation electronic (54) includes a software routine (62) for determining the second lowest support foot related support load measurement value for one of each sampling cycle and for the comparison thereof with a stability determining threshold value.

3. Work device according to claim 1 or 2, thereby characterized, that the evaluation electronic (54) includes a software routine for determining the highest support foot related support load measurement value for one of each sampling cycle and for the comparison thereof with a stability determining threshold value.

4. Work device according to one of claims 1 through 3, thereby characterized, that the evaluation electronic (54) includes a threshold value provider for predetermining a minimal force.

5. Work device according to one of claims 1 through 4, thereby characterized, that the evaluation electronic (54) includes a threshold value provider for providing an advance warning force.

6. Work device according to one of claims 1 through 5, thereby characterized, that the evaluation electronic (54) includes a threshold value provider for providing a maximal force.

7. Work device according to one of claims 1 through 6, thereby characterized, that the evaluation electronic (54) is connected with a control device (56) for controlling the work boom (14).

8. Work device according to one of claims 1 through 7, thereby characterized, that the evaluation electronic (54) is connected with a control device (56) for controlling a concrete pump.

9. Work device according to one of claims 1 through 8, thereby characterized, that the evaluation electronic (54) is connected with an acoustic and/or optical signal provider (58).

10. Work device according to one of claims 1 through 9, thereby characterized, that in each support foot (26) two force sensors (32, 34) of preferably the same type are provided, which are provided in independent measurement circuits (36, 38) for providing a support load dependent measurement signal.

11. Work device according to claim 10 or 11, thereby characterized, that the evaluation electronic (54) includes a software routine (60) for pair-wise comparison with respect to their agreement of the support load measurement values derived from the support load measurement signals.

13. Work device according to one of claims 1 through 12, thereby characterized, that the force sensors (32, 34) comprise a strain measuring strip.

14. Work device according to one of claims 1 through 12, thereby characterized, that the force sensors (32, 34) are piezoelectric sensors.

15. Work device according to one of claims 1 through 14, thereby characterized, that the electrical measuring circuits (36, 38) include a bridge switch, in one branch of which the associated force sensor (32, 34) is provided.

16. Work device according to claim 15, thereby characterized, that the measuring circuits (36, 38) include an operation amplifier (40, 42) connected on the input side with diagonal pick-offs (50, 52) from the bridge switch.

17. Work device according to one of claims 1 through 16, thereby characterized, that the electrical measuring circuits (36, 38) exhibit a measurement precision decreasing from low to high support foot related support load measurement value.

18. Work device according to one of claims 1 through 17, thereby characterized, that the electrical measuring circuits (36, 38) are adjusted to an increased measurement precision in the measuring range below approximately 30%, preferably below 15%, of the support foot related maximal load.

19. Work device according to one of claims 1 through 18, thereby characterized, that the measurement precision of the electrical measurement circuit (36, 38) is selectively reversible.

20. Work device according to one of claims 1 through 19, thereby characterized, that the force sensors (32, 34) are provided in a foot element (44, 46) which can preferably be retrofit securable to the support foot (26).

21. Work device according to claim 20, thereby characterized, that the at least one measuring circuit (36, 38) is integrated in the associated foot element (44, 46).

22. Work device according to claim 21, thereby characterized, that the at least one measuring circuit (36, 38) is coupled via a galvanic or wireless transmission path with the evaluation electronic (54).

12. Mobile work device, in particular mobile concrete pump, which a vehicle chassis (10), with two forward and two rearward support struts (20) extendable from a transport position to at least one support position and with respectively one preferably telescopic support foot (26) supportable upon the ground (28), with a work boom (14), preferably a concrete distribution boom, extendable from a driving position to a work position projecting beyond the vehicle chassis and rotatable about a vehicle chassis-fixed vertical axis (13), with a measurement device (30) provided in the area of the support feet (26) for determining the respective support loads and with a support stability monitoring device evaluating or responding to the output signals of the measurement assemblies, thereby characterized, that in each support foot (26) two force sensors (32, 34) of preferably the same type are provided, which are provided in independent measurement circuits (36, 38) for providing a support load dependent measurement signal, the monitoring device (54) including a software routine (60) for pair-wise comparison with respect to their agreement of the support load measurement values derived from the support load measurement signals.

23. Foot element for securing to a support foot (26) of a support strut (20) of a mobile work device, in particular a mobile concrete pump, supportable in a support position upon a substrate (28), characterized by at least one force sensor (32, 34) responsive to the input of a support load dependent force, within an electrical measurement circuit (36, 38) for providing a support load dependent measurement signal.

24. Foot element according to claim 23, thereby characterized, that two force sensors (32, 34) of preferably the same type are provided in separate measurement circuits (36, 38).

25. Foot element according to claim 23 or 24, thereby characterized, that the foot sensors (32, 34) include a strain measurement strip.

26. Foot element according to claim 24 or 25, thereby characterized, that force sensors (32, 34) are piezoelectric elements.

27. Foot element according to one of claims 23 through 26, thereby characterized, that each measurement circuit (36, 38) includes a bridge switch, in which one branch of the associated force sensor (32, 34) is provided.

28. Foot element according to claim 27, thereby characterized, that each measuring circuit (36, 38) includes an operation amplifier (40, 42) connected on the input side with the bridge switch.