Mobile working machine provided with stability monitoring

• US 7,012,540 B2
• Filed: 02/27/2002
• Issued: 03/14/2006
• Est. Priority Date: 03/02/2001
• Status: Expired due to Fees

• Current Assignee: Putzmeister Engineering GmbH
• Original Assignee: Putzmeister Aktiengesellschaft
• Inventors: Petzold, Wolf-Michael, Gelies, Stephan, Alwes, Dieter
• Primary Examiner(s): Lee, Benjamin C.
• Application Number:
  US10/469,408
• Publication Number:
  US 20040119597A1
• Time in Patent Office: 1,476 Days
• Field of Search: 340665-667, 340/679, 340/685, 340/682, 340/686.1, 340/689, 340/686.5
• 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. A mobile work device comprising

a vehicle chassis (10),

two forward and two rearward support struts (20) extendable from a transport position to at least one support position and supportable upon the ground (28) with respectively one telescopic support foot (26),

a work boom (14) extendable from a driving position to a work position projecting beyond the vehicle chassis and rotatable about a vehicle chassis-fixed vertical axis (13),

a measurement device (30) provided in the area of the support feet (26) for determining the respective support loads and

a support stability monitoring device responsive to the output signals of the measurement device,

wherein at least one force sensor (32, 34) is provided for each support foot (26), wherein each force sensor is provided in an electrical measurement circuit (36, 38) for output of a support load dependent measurement signal, wherein 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, and wherein the electrical measuring circuits (36, 38) exhibit a measurement precision which decreases going from low to high support foot derived support load measurement values.

2. A work device according to claim 1, wherein the electrical measuring circuits (36, 38) are adjusted to an increased measurement precision in the measuring range below approximately 30% of the support foot derived maximal load.

3. A work device according to claim 1, wherein the measurement precision of the electrical measurement circuit (36, 38) is selectively reversible.

4. A work device according to claim 1, wherein two force sensors (32, 34) are provided in each support foot (26), which are provided in independent measurement circuits (36, 38) for providing a support load derived measurement signal.

5. A work device according to claim 4, wherein 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.

6. A work device according to claim 1, wherein the evaluation electronic (54) includes a software routine (62) for determining the second lowest support foot related support load measurement value for each sampling cycle and for the comparison thereof with a stability determining threshold value.

7. A work device according to claim 1, wherein the evaluation electronic (54) includes a software routine for determining the highest support foot derived support load measurement value for each sampling cycle and for the comparison thereof with a stability determining threshold value.

8. A work device according to claim 1, wherein the evaluation electronic (54) includes a threshold value provider for predetermining a minimal force.

9. A work device according to claim 1, wherein the evaluation electronic (54) includes a threshold value provider for providing an advance warning force.

10. A work device according to claim 1, wherein the evaluation electronic (54) includes a threshold value provider for providing a maximal force.

11. A work device according to claim 1, wherein the evaluation electronic (54) is connected with a control device (56) for controlling the work boom (14).

12. A work device according to claim 1, wherein the evaluation electronic (54) is connected with a control device (56) for controlling a concrete pump.

13. A work device according to claim 1, wherein the evaluation electronic (54) is connected with an acoustic and/or optical signal provider (58).

14. A work device according to claim 1, wherein the force sensors (32, 34) comprise a strain measuring strip.

15. A work device according to claim 1, wherein the force sensors (32, 34) are piezoelectric sensors.

16. A work device according to claim 1, wherein the electrical measuring circuits (36, 38) include a bridge switch, in one branch of which the associated force sensor (32, 34) is provided.

17. A work device according to claim 16, wherein 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.

18. A work device according to claim 1, wherein the force sensors (32, 34) are provided in a foot element (44, 46) that can be retrofitted securely to the support foot (26).

19. A work device according to claim 18, wherein the at least one measuring circuit (36, 38) is integrated in the associated foot element (44, 46).

20. A work device according to claim 19, wherein the at least one measuring circuit (36, 38) is coupled via a galvanic or wireless transmission path with the evaluation electronic (54).

21. A mobile work device as in claim 1, wherein said mobile work device is a mobile concrete pump, and wherein said a work boom (14) is a concrete distribution boom.

22. A work device according to claim 1, wherein the electrical measuring circuits (36, 38) are adjusted to an increased measurement precision in the measuring range below approximately 15% of the support foot derived maximal load.

23. A mobile work device comprising

a vehicle chassis (10),

two forward and two rearward support struts (20) extendable from a transport position to at least one support position and supportable upon the ground (28) with respectively one telescopic support foot (26)

a work boom (14) extendable from a driving position to a work position projecting beyond the vehicle chassis and rotatable about a vehicle chassis-fixed vertical axis (13)

a measurement device (30) provided in the area of the support feet (26) for determining the respective support loads and

a support stability monitoring device responsive to the output signals of the measurement device,

wherein at least one force sensor (32, 34) is provided for each support foot (26), wherein each force sensor is provided in an electrical measurement circuit (36, 38) for output of a support load dependent measurement signal, wherein 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, and wherein the evaluation electronic (54) includes a software routine (62) for determining the second lowest support foot related support load measurement value for each sampling cycle and for the comparison thereof with a stability determining threshold value.

24. A mobile work device as in claim 23, wherein said mobile work device is a mobile concrete pump, and wherein said a work boom (14) is a concrete distribution boom.