AU732748B2

AU732748B2 - Hydraulic unit

Info

Publication number: AU732748B2
Application number: AU62840/98A
Authority: AU
Inventors: Gisela Weber
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-03-07
Filing date: 1998-03-06
Publication date: 2001-04-26
Anticipated expiration: 2018-03-06
Also published as: AT408681B; EP0965000A1; WO1998040630A1; AU6284098A; JP2001515568A; ATA39797A

Description

Hydraulic unit This present invention concerns a hydraulic unit to supply and control lifts, elevating platforms, tailgates, gates etc.

driven by hydraulic cylinders, comprising a hydraulic pump driven by a motor via a drive shaft, which pump is connected, via manually actuatable relay valves, to a hydraulic medium supply and to at least one outlet port of the hydraulic unit, wherein the motor, the hydraulic pump and the relay valves are arranged in a housing as an independent unit.

The object of the invention is to produce a hydraulic unit which in the case of an emergency, when the motor fails, can be driven to enable, for example, the lowering of the lift, the elevating platform etc. or the closing of the tailgate, the gate or the like. This objective is achieved with a hydraulic unit of the type mentioned in the introduction by that the drive shaft protrudes from the housing to the outside and a crank handle for the emergency operation is fitted together with a gearbox in a detachable manner to the accessible end of the drive shaft.

With the construction according to the invention it is achieved on the one hand that in normal operation the crank handle together with the gearbox can be removed, reducing the weight and dimensions of the unit, and on the other hand in an emergency mode only the normal motor function ceases, because according to the invention the hydraulic pump, with the motor blocked, is driven via the normal motor shaft, while in practice a form-locked connection is provided between the motor shaft and the push-on shaft of the gearbox.

In the case of a design known from EP-A-444 387 only a crank handle pump drive is provided, i.e. there is no motor, since it has to be separated from the pump shaft prior to attaching the crank handle. This is not necessary according to this invention. The motor remains in its place in a housing, boxlike enclosed and forming an independent unit, and only the AMENDED PAGE emergency drive is fitted. Therefore the construction according to the invention has a completely different design from that of the known one.

It has to be also mentioned that from DE-A-27 58 745 another design is known, which at one end of the housing of the hydraulic unit has a drive motor and at the other end a crank handle, while between the pump and each drive a clutch is fitted. The disadvantage of this design, when compared with this invention, is that its overall dimension are considerable, it does not form an enclosed unit and two special clutches have to be provided.

AMENDED PAGE In a preferred manner a one-way clutch is fitted between the motor and the crank handle, preventing the dragging of the crank handle when the motor running.

The invention is explained in the following in detail based on an embodiment illustrated in the drawings. They show in: Fig.l a hydraulic circuit of a hydraulic unit shown in side view in Fig.2 and in top view in Fig.3 (in each case the side wall is shown broken).

The hydraulic unit is constructed as a totally independent unit in a box-shaped housing 1 and comprises a hydraulic pump 4 driven by an electric motor 2 via a drive shaft 3, which pump evacuates hydraulic medium from a supply 6 via a filter 5 and delivers it under pressure to the outlet ports A, B via a twoway valve 7 to two parallel branches, each of them having a relay valve 8 and a volume control valve 9. To the outlet connections A, B feed lines a, b (not illustrated) of parallel hydraulic cylinders of, for example, a tailgate may be connected. To the other terminal of the relay valve 7 a return line 20 returning to the supply 6 is connected, and furthermore a safety valve 21 and a measuring terminal 22 for testing are included in the circuit.

The electric motor 2 has a magnetic starter switch 10 and it can, just like the relay valves 8, controlled via an electric control 11 with push-buttons 12 and a main switch 13.

The drive shaft 3 protrudes from the housing 1 to the outside 14. A crank handle 16 is fitted in a detachable manner to that end of the drive shaft 3 which is accessible from the outside to actuate the motor 2 in an emergency. Furthermore, the relay valves 8 have hand levers 17 for manual actuation in case of an emergency.

The gearbox 15 is preferably a reducing transmission with a crank handle:drive shaft reduction ratio of 3:1 or 5:1, for example.

To simplify matters, the gearbox 15 may be omitted and the crank handle 16 may be attached directly to the drive shaft 3.

A one-way clutch 18 may be fitted optionally between the motor and the crank handle 16 to prevent the dragging of the crank handle 16 with the motor 2 running.

Claims

1. A hydraulic unit to supply and control lifts, elevating platforms, tailgates, gates etc. driven by hydraulic cylinders, comprising a hydraulic pump driven by a motor via a drive shaft which pump is connected, via manually actuatable relay valves to a hydraulic medium supply and to at least one outlet port B) of the hydraulic unit, wherein the motor, the hydraulic pump and the relay valves are arranged in a housing as an independent unit, characterised in that the drive shaft protrudes from the housing to the outside (14) and a crank handle (16) for the emergency operation is fitted together with a gearbox (15) in a detachable manner to the accessible end of the drive shaft

2. A hydraulic unit according to claim 1, characterised in that on the drive shaft a one-way clutch (18) is fitted between the motor and the crank handle (16). AMENDED PAGE