Lifting apparatus

• US 5,481,769 A
• Filed: 01/12/1994
• Issued: 01/09/1996
• Est. Priority Date: 01/15/1993
• Status: Expired due to Fees

• Current Assignee: Dewert Antriebs-Und Systemtechnik GmbH& Company KG (Phoenix Mecano AG)
• Original Assignee: Dewert Antriebs-Und Systemtechnik GmbH& Company KG (Phoenix Mecano AG)
• Inventors: Schneider, Johannes
• Primary Examiner(s): TRETTEL, MICHAEL
• Application Number:
  US08/180,876
• Time in Patent Office: 727 Days
• Field of Search: 5/13, 5/616, 5/617, 5/425, 464/39, 254/7 R, 254/7 B, 254/7 C
• US Class Current: 5/617
• CPC Class Codes: A47C 20/041 by electric motors
• CPC Class Codes: B66F 7/0608 driven by screw or spindle
• CPC Class Codes: B66F 7/065 Scissor linkages, i.e. X-configuration

Abstract

A lifting device for swiveling a part of a piece of furniture includes a scissor jack attached to the part being swiveled and operated by a drive unit having a spindle and a gear motor which is connected to the scissor jack and runs along the spindle. Incorporated in the drive unit is a safety mechanism for stopping a movement of the scissor jack upon occurrence of a blockage. The safety mechanism includes a pair of disks rotatable about the spindle and engaging each other via a complementary tooth gearing provided about the perimeter of each disk. One disk is stationary and the other disk is a spring-loaded disk which is displaceable in axial direction relative to the one disk. In this manner, the disks can be disengaged upon blockage during downward movement of the scissor jack to disconnect the gear motor from its output element and to prevent a further movement of the scissor jack.

Claims

1. A lifting device for swiveling parts of a piece of furniture;

comprising;

a scissor jack connected to a part being swiveled;

drive means for actuating said scissor jack, said drive means including a spindle and a gear motor connected to said scissor jack; and

safety means incorporated in said drive means for stopping movement of said scissor jack upon occurrence of a blockage, said safety means including a pair of disks engaging each other during normal operation via a complementary tooth gearing extending about the perimeter of each said disk, with one of said disks being stationary and the other one of said disks being a spring-loaded disk which is displaceable in axial direction for allowing disengagement of said disks upon blockage of a downward movement.

2. A lifting apparatus as defined in claim 1 wherein said disks are provided in form of a ring gear.

3. A lifting apparatus for swiveling parts of a piece of furniture;

comprising;

a metallic scissor jack connected to the part being swiveled;

drive means for actuating said scissor jack, said drive means including a spindle and a gear motor connected to said scissor jack; and

safety means for stopping movement of said scissor jack upon occurrence of a blockage, said safety means including a sensor unit forming with said scissor jack a contact or approximation detector for generating a signal upon contact or approach of said scissor jack, and a control and evaluator unit receiving the signal from said sensor unit for generating control signals for said drive means,

wherein said safety means includes a switching amplifier for enhancing the control signals of said control and evaluator unit and a power source incorporated in said switching amplifier so that a supply of power to said sensor unit and said control and evaluator unit is provided only when said drive means is operated.

4. A lifting apparatus for swiveling parts of a piece of furniture;

comprising;

a metallic scissor jack connected to the part being swiveled;

drive means for actuating said scissor jack, said drive means including a spindle and a gear motor connected to said scissor jack; and

safety means for stopping movement of said scissor jack upon occurrence of a blockage, said safety means including a sensor unit forming with said scissor jack a contact or approximation detector for generating a signal upon contact or approach of said scissor jack, and a control and evaluator unit receiving the signal from said sensor unit for generating control signals for said drive means,

wherein said contact or approximation detector is an inductive proximity switch, with said scissor jack forming a detector electrode.

5. A lifting apparatus as defined in claim 4 wherein said switching amplifier includes a relay.

6. A lifting apparatus for swiveling parts of a piece of furniture;

comprising;

a metallic scissor jack connected to the part being swiveled;

drive means for actuating said scissor jack, said drive means including a spindle and a gear motor connected to said scissor jack; and

safety means for stopping movement of said scissor jack upon occurrence of a blockage, said safety means including a sensor unit forming with said scissor jack a contact or approximation detector for generating a signal upon contact or approach of said scissor jack, a control and evaluator unit receiving the signal from said sensor unit for generating control signals for said drive means, and a trimmer potentiometer for adjusting the sensitivity of said sensor unit.

7. A lifting device for swiveling a part of a piece of furniture;

comprising;

a lifting member connected to the part being swiveled;

drive means for actuating said lifting member, said drive means including a spindle and a gear motor, said gear motor being connected to said lifting member and placed upon said spindle for axial movement along said spindle; and

safety means operatively connected to said drive means for stopping a movement of said lifting member upon occurrence of a blockage, said safety means including a pair of disks rotatable about said spindle and engaging each other via a complementary tooth gearing, one of said disks being stationary and the other one of said disks being a spring-loaded disk and displaceable in axial direction relative to said one disk for allowing disengagement of said disks upon blockage of a movement of said lifting member.

8. A lifting apparatus as defined in claim 7, and further comprising a protective means for shielding said lifting member from outside, said protective means including a stationary reel and a safety web extending essentially over a width of said lifting member, said safety web having one end connected to said lifting member and another end secured to said reel for allowing winding and unwinding thereof in synchronism with a movement of said lifting member.

9. A lifting apparatus as defined in claim 7 wherein said lifting member is of metal, said safety means including a sensor unit forming with said lifting member a contact or approximation detector for generating a signal upon contact or approach of said lifting member, and a control and evaluator unit receiving the signal from said sensor unit for generating control signals for said drive means.

10. A lifting apparatus as defined in claim 9 wherein said safety means includes a switching amplifier for enhancing the control signals of said control and evaluator unit and a power source incorporated in said switching amplifier so that a supply of power to said sensor unit and said control and evaluator unit is provided only when said drive means is operated.

11. A lifting apparatus as defined in claim 9 wherein said contact and approximation detector is an inductive proximity switch, with the lifting member forming a detector electrode.

12. A lifting apparatus as defined in claim 9 wherein said safety means includes a trimmer potentiometer for adjusting a sensitivity of said sensor unit.

13. A lifting apparatus as defined in claim 9 wherein said switching amplifier includes a relay.