Hydraulic elevator installation

• US 4,351,415 A
• Filed: 08/12/1980
• Issued: 09/28/1982
• Est. Priority Date: 10/06/1978
• Status: Expired due to Term

• Current Assignee: Shimadzu Corporation
• Original Assignee: Shimadzu Corporation
• Inventors: Kita, Yasuo
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Duncanson, Jr., W. E.
• Application Number:
  US06/177,386
• Time in Patent Office: 777 Days
• Field of Search: 187/29
• US Class Current: 187/285
• CPC Class Codes: B66B 1/24 Control systems with regulation, i.e. with retroactive action, for influencing travelling speed, acceleration, or deceleration
• CPC Class Codes: B66B 1/405 for hydraulically actuated elevators
• CPC Class Codes: F15B 21/14 Energy-recuperation means

Abstract

This invention provides a hydraulic elevator installation in which a variable hydraulic pump supplies pressure fluid to a hydraulic actuator connected to an elevator cage. The hydraulic pump functions to operate as a hydraulic motor with the pressure fluid discharged from the hydraulic actuator when the elevator is descending. The hydraulic pump is driven by an induction motor. The induction motor begins to function as an induction generator, recovering potential energy on the high speed rotation of the hydraulic motor while it is generating electricity. When the hydraulic pump has started its function as the hydraulic motor.

Claims

1. A hydraulic elevator installation comprising:

(a) an elevator cage (11);

(b) a hydraulic actuator, including a cylinder (14) having a plunger (13) connected to said elevator cage (11);

(c) a hydraulic pump (16) having a variable output for supplying said hydraulic actuator with pressure fluid wherein said pump (16) functions to operate as a hydraulic motor, driven with the pressure fluid discharged from said cylinder (14) when said elevator cage (11) is descending, said pump being adjustable to maintain the rotational direction of a drive shaft of the pump the same during ascending and descending of said elevator cage;

(d) an induction motor (17) for driving said hydraulic pump (16), wherein said induction motor (17), when driven at a speed over the synchronous speed by means of said hydraulic motor (16) functions to operate as an induction generator; and

,

(e) a power source (18) for driving said induction motor (17).

2. In a hydraulic elevator installation, having an elevator cage (11), with a cage floor (12), a hydraulic actuator, including a vertical plunger (13) connected to the cage floor with a vertical cylinder (14) housing said plunger, a hydraulic pump (16) having a variable output coupled to said hydraulic actuator for supplying said hydraulic actuator with pressure fluid, and an electric motor coupled to said pump,

the improvement wherein;

(a) said variable hydraulic pump is a piston pump with a slide block and pintle mounted on said slide block, said pump being adjustable to maintain the rotational direction of a drive shaft of the pump the same during ascending and descending of said elevator cage; and

,

(b) said electric motor (17) is an induction motor, whereby said pump functions as a hydraulic motor driven by hydraulic fluid discharged from said cylinder; and

, said induction motor becomes a generator; and

,

(c) a load circuit (25) coupled to said induction motor.