GB2133075A

GB2133075A - Displacement device, e.g. for sliding doors

Info

Publication number: GB2133075A
Application number: GB08333785A
Authority: GB
Inventors: Yuichi Suga
Original assignee: Nabco Ltd
Current assignee: Nabco Ltd
Priority date: 1982-12-20
Filing date: 1983-12-19
Publication date: 1984-07-18
Also published as: KR880001424Y1; GB8333785D0; BR6301759U; JPS5996270U; FR2538022B1; GB2133075B; FR2538022A1; KR840007129A; JPH0218231Y2

Abstract

A linearly displaceable element (e.g. a piston 21 in a fluid cylinder 20) is secured to one door by a piston rod extension 22a, and has a threaded aperture 30. A collar 31 with an oppositely threaded aperture 32 is connected to the other door. A rod 27 has two spaced regions 28,29 with opposed threads, engaging said two apertures 30,32. Displacing the element 21 causes the rod 27 to rotate, which displaces the collar 31 in the opposite direction from the element 21. <IMAGE>

Description

SPECIFICATION Displacement device, e.g. for sliding doors The present invention relates to a displacement device, particularly for sliding doors.

FIGS. 1 and 2 of the accompanying drawings illustrate conventional devices for driving sliding doors.

The driving device shown in FIG. 1 includes a driving fluid cylinder 3 and two pulleys 4, 5 disposed upwardly of sliding doors 1, 2 to be driven. An endless belt 6 is trained around the pulleys 4, 5, and connectors 8, 9 coupled to the doors 1, 2, respectively, are connected to upper and lower runs, respectively, of the endless belt 6.

When a fluid under pressure is supplied into and discharged from the driving fluid cylinder 3, a piston in the driving fluid cylinder 3 is moved in the direction of the arrow A to cause the connector 8 connected to a distal end 7 of the piston rod to move in the direction of the arrow A.

At the same time, the door 2 is moved by the belt 6 and the connector 9 in the direction of the arrow B. Accordingly, the doors 1, 2 are opened away from each other. When the piston in the driving cylinder 3 is driven in the direction of the arrow B, the door 1 is moved by the connector 8 in the direction of the arrow B, while the door 2 is moved by the belt 6 and the connector 9 in the direction of the arrow A. Thus, the doors 1, 2 are closed toward each other.

The driving device ilustrated in FIG. 2 is composed of a driving fluid cylinder 11, racks 12, 13, and a pinion 14 held in mesh with the racks 12, 13. The driving fluid cylinder 11 has a piston rod with its distal end 1 5 connected to a connector 1 6 coupled to a door 1. The rack 12 is also coupled to the connector 1 6. The rack 13 is coupled to a connector 1 7 mounted on another door 2.

When a fluid under pressure is supplied into and discharged from the driving fluid cylinder 11, a piston in the driving fluid cylinder 11 is moved in the direction of the arrow C, the door 1 and the rack 1 2 are moved also in the direction of the arrow C by the connector 16. At the same time, the rack 1 3 is moved in the direction of the arrow D by the pinion 14 meshing the rack 12, whereupon the door 2 is moved in the direction of the arrow D by the connector 1 7. Thus, the doors 1, 2 are moved away from each other.In response to movement of the piston in the driving fluid cylinder 11 in the direction of the arrow D, the door 1 and the rack 12 2 are driven in the direction of the arrow D by the connector 1 6, and the door 2 is moved in the direction of the arrow C by the connector 1 7 through the pinion 1 4 and the rack 13. Accordingly, the doors 1, 2 are closed.

The conventional door driving devices as shown include, in addition to the driving fluid cylinder 3 or 11 , the mechanism for transmitting the driving power from the driving fluid cylinder separately to the doors 1, 2, Accordingly, the location in which the driving device is stored needs spaces for the driving fluid cylinder and the transmitting mechanism, respectively.

There have in recent years been demands for more lightweight electric car bodies on which door driving devices are mounted, and for smaller spaces for housing therein door driving devices, particularly, driving devices having a reduced height (corresponding to H in FIGS. 1 and 2). Door driving devices for use in buildings are also desired to be slightly in appearance through the reduction of the size of a space in which the device is accommodated.

According to the present invention there is provided a displacement device comprising: a driveable means which is driveable selectively in a forward or a reverse direction, said means being connectable to a first article to be displaced, and having a threaded engagement means extending in the driving direction; an elongate member having a first threaded engagement means complementary with that of the driveable means and, spaced therefrom, a second threaded engagement means whose thread is in the opposite sense; and means for connection to a second article to be displaced, said means having a threaded engagement means complementary with said second threaded engagement means of the elongate member, the arrangement being such that, in use, said first and second engagement means are engaged with their complementary engagement means, and driving of said driveable means causes rotation of said elongate member whereby the connection means is driven in the opposite direction.

By means of the present invention one can provide a device for driving sliding doors which has a reduced height by incorporating in a driving fluid cylinder a mechanism for transmitting the driving power separately to a pair of sliding doors.

A preferred embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which: FIGS. 1 and 2 are schematic diagrams showing conventional devices for driving sliding doors; FIG. 3 is a longitudinal cross-sectional view of a device embodying the present invention arranged for driving sliding doors; and FIG. 4 is an enlarged fragmentary longitudinal cross-sectional view of a driving fluid cylinder in the device of FIG. 3.

As shown in FIGS. 3 and 4, a device for driving sliding doors includes a driving fluid cylinder 20 disposed upwardly of a pair of sliding doors 1, 2 and including a piston 21 slidably disposed therein and connected to a piston rod 22 having a distal end 22a coupled by a pin 24 to a connector 23 projecting from an upper edge of the door 1. The driving fluid cylinder 20 includes a head 25 housing therein a pair of bearings 26 by which a screw shaft 27 is rotatably supported, the screw shaft 27 extending axially through the head 25.

The screw shaft 27 has a threaded portion 28 extending into the driving fluid cylinder 20 and having a lefthand thread of a large helix angle. The threaded portion 28 extends threadedly through an internally threaded bore 30 in the piston 21 and into a bore 22b in the piston rod 22, the threaded portion 28 having a distal end located near a distal end 22a of the piston rod 22. The screw shaft 27 also includes a threaded portion 29 extending coaxially with and remotely from the threaded portion 28. The threaded portion 29 projects from the driving fluid cylinder 20 and has a righthand thread, the threaded portion 29 extending threadedly through an internally threaded bore 32 in a connector 31 projecting from an upper edge of the door 2.As an alternative, the threaded portion 28 and the internally threaded bore 30 may have righthand threads, and the threaded portion 29 and the internally threaded bore 32 may have lefthand threads.

Operation of the door driving device thus constructed is as follows: When a directional control valve (not shown) is actuated to supply a fluid under pressure into the driving fluid cylinder 20 through a port 33 and discharge a fluid under pressure out of the driving fluid cylinder 20 through a port 34, the piston 21 and hence the piston rod 22 are moved in the direction of the arrow E, thereby moving the distal end 22a, the connector 23 and the door 1 in the direction of the arrow E. In response to the movement of the piston 21, the threaded portion 28 threaded in the internally threaded bore 30 is caused to rotate the screw shaft 27 about its own axis in the direction of the arrow G. The piston 21 is prevented from rotating about its own axis since it is coupled with the connector 23.Since the thread on the threaded portion 29 of the screw shaft 27 is opposite to that on the threaded portion 28, the connector 31 threaded over the threaded portion 29 and thus the door 2 are moved in the direction of the arrow F. Therefore, the doors 1,2 are moved away from each other.

When the directional control valve is actuated to supply the fluid under pressure into the driving fluid cylinder 20 through the port 34 and discharge the fluid under pressure from the driving fluid cylinder 20 through the port 33, the piston 21 and the piston rod 22 are moved in the direction of the arrow F, forcing the distal end 22a, the connector 23 and the door 1 to move in the direction of the arrow F. This movement of the piston 21 causes the screw shaft 27 to rotate about its own axis in the direction of the arrow K.

In response to the rotation of the screw shaft 27 in the direction of the arrow K, the connector 31 threaded over the screw shaft 27 enables the door 2 to move in the direction of the arrow E.

Consequently, the doors 1,2 are moved toward each other until they are closed as shown in FIG. 3.

With the arrangement as shown, the mechanism for transmitting the driving power from the driving fluid cylinder separately to the doors is substantially accommodated in the driving fluid cylinder. As a result, the door driving device is of a reduced height and small in overall size. The speed at which the doors are opened and closed can be varied by changing the screw pitch of the screw shaft.

Although a certain preferred embodiment has been shown and described, it should be understood that many changes and modifications may be made therein without departing from the scope of the invention.

Claims

1. A displacement device comprising: a driveable means which is driveable selectively in a forward or a reverse direction, said means being connectable to a first article to be displaced, and having a threaded engagement means extending in the driving direction; an elongate member having a first threaded engagement means complementary with that of the driveable means and, spaced therefrom, a second threaded engagement means whose thread is in the opposite sense; and means for connection to a second article to the displaced, said means having a threaded engagement means complementary with said second threaded engagement means of the elongate member, the arrangement being such that, in use, said first and second engagement means are engaged with their complementary engagement means, and driving of said driveable means causes rotation of said elongate member whereby the connection means is driven in the opposite direction.

2. A displacement device according to claim 1 wherein said driveable means comprises a piston, the displacement device further including a fluid cylinder in which said piston is driveable by fluid pressure.

3. A displacement device according to claim 1 or claim 2 wherein said elongate member comprises a screw shaft having an externally threaded portion constituting said first threaded engagement means and extending threadedly through a coaxial threaded aperture in said driveable means.

4. A displacement device according to claim 3 as appendant on claim 2 wherein said piston is fast with a coaxial piston rod which extends axially beyond the cylinder and is arranged to be connectable to said first article; said piston having said threaded axial aperture which is continuous with a coaxial bore in said piston rod in which an end portion of said screw shaft is receivable.

5. A displacement device according to claim 4 wherein said fluid cylinder has a head including at least one rotary bearing through which said screw shaft extends, and in which it is rotatably supported.

6. A displacement device according to any of claims 3 to 5 in which the second threaded engagement means of the screw shaft has an external thread, and the connection means has a complementary internal thread.

7. A displacement device substantially as described herein with reference to and as illustrated in Figs. 3 and 4 of the accompanying drawings.

8. A sliding door assembly including a pair of sliding doors and a displacement device according to any preceding claim.