Apparatus for closing sliding doors on vehicle

A door closing apparatus facilitates simultaneously opening of a pair of sliding doors by pulling a manual release wire. Specifically, by pulling the manual release wire, a belt 82 fixed to the manual release wire moves with belt pulleys and two hooks to contact and move respective movable frames to the opening directions thereof. Due to these movements, permanent magnets 31A, 31B rotate, through respective racks to release the holding of the closed doors. Thus, the sliding doors can be opened manually.

FIELD OF THE INVENTION 
The present invention relates to a door closing apparatus for automatically 
closing a pair of sliding doors disposed at a passenger entrance on a 
rolling stock, such as an electric car and a train. More specifically the 
present invention relates to a door closing apparatus which facilitates 
opening the sliding doors manually in the event of an emergency or at 
other times when it is really necessary to open the doors. 
BACKGROUND 
The Japanese Unexamined Laid Open Patent Application No. H06-115429 
discloses a door closing apparatus which opens and closes a pair of 
sliding doors on vehicle with a linear motor and holds the doors in the 
closed state with a permanent magnet. FIG. 4 is a front view of a main 
part of this conventional door closing apparatus right before completing 
to close the doors, an FIG. 5 is a cross section along A--A of FIG. 4. 
FIGS. 4 and 5 chiefly show an upper right side of a left one of the 
symmetrically arranged sliding door pair. A left sliding door 1A and a 
right sliding door 1B are hung with a plurality of door sheaves 3 on a 
supporting rail 2 extending horizontally along a side wall 5 of the 
vehicle. The sliding doors 1A and 1B open and close a passenger entrance 
of the vehicle. A stopper 74 is fixed to the side wall 5. 
A coupling means 20 for coupling a slider 4b of a linear motor and the 
sliding door 1A includes a driving plate 21 fixed to the slider 4b and a 
passive plate 22 fixed to the sliding door 1A. The sliding door 1A is 
opened and closed with a gap X between the plates 21 and 22 in the 
opening-and-closing direction. 
A movable magnetic pole 39 is fixed via an adjustable joint 38 to the 
sliding door 1A. A closed door holding means 30A is fixed to the side wall 
5 facing opposite to the magnetic pole 39. The closed door holding means 
30A includes a cylindrical permanent magnet 31A which magnetically fixes 
opposed facing N and S poles in the radial direction thereof and a pair of 
pole shoes 32A surrounding the N and S poles. Each of the pole shoes has a 
non-magnetic portion at the end thereof. In the state shown in FIG. 5, the 
closed door holding means 30A does not attract the movable magnetic pole 
39, since the internal magnetic path of the closed door holding means 30A 
is open. When the permanent magnet 31A rotates by 90 degrees of angle from 
the position shown in FIG. 5, the internal magnetic path of the closed 
door holding means 30A is closed so that the closed door holding means 30A 
attracts the movable magnetic pole 39. Thus, the closed door holding means 
30A releases and holds the closed state of the sliding door 1A by a 
quarter turn of permanent magnet 31A. Another closed door holding means 
30B for the right sliding door 1B is independent from its counterpart 30A 
and arranged in mirror symmetry with respect to the closed door holding 
means 30A. Preferable holding power due to the magnetic force of the 
permanent magnet 31A is around 100 kg. 
A gear 42 which couples with a rack 41 is fixed to the permanent magnets 
31A of the closed door holding means 30A. The rack 41 and the gear 42 
constitutes a movement converting means 40 for converting a linear 
movement to a rotational movement. The converting means 40 may comprise a 
link mechanism. The rack 41 is fixed to a movable frame 43 which moves on 
a not shown support mechanism in the opening-and-closing direction of the 
sliding doors so as to rotate the permanent magnet 31A by 90 degrees of 
angle. 
An attracting-and-releasing means 50 is disposed between the slider 4b and 
the movable frame 43. The attracting-and-releasing means 50 includes an 
adjustable joint 51 and a magnet 52 for attracting the adjustable joint 
51. The adjustable joint 51 is attracted to the magnet 52 when the 
adjustable joint 51 is positioned, e.g., within the gap X from the magnet 
52, and the adjustable joint 51 is not attracted to the magnet 52 as far 
as the adjustable joint 51 is positioned for more than the gap X away from 
the magnet 52. Preferable attracting force of the attracting-and-releasing 
means 50 is around 10 kg. The attracting-and-releasing means 50 may 
comprise a latch mechanism. 
A manual releasing means 60 constituting a remote operating mechanism which 
includes a flexible sheath 61 and a wire 62 is coupled to the movable 
frame 43. When the wire 62 is pulled by a not shown manual releasing 
lever, the permanent magnet 31A is rotated via the movable frame 43, i.e. 
the rack 41, and the closed door holding means 30A releases the held 
movable magnetic pole 39. A touch sensor 71 is disposed on the plane on 
which the closed door holding means 30A or 30B attracts the movable 
magnetic pole 39 as a safety measure for transmitting a signal indicating 
the closed state of the pertinent door. 
The conventional door closing apparatus operates as follows. As the slider 
4b of the linear motor moves in the closing direction, the coupling means 
20 moves, with the gap X left behind, to close the sliding door 1A, and 
brings the attracting-and-releasing means 50 to the state right before the 
attraction. As the sliding door 1A further closes, the slider 4b drives 
the movement converting means 40 through the attracting-and-releasing 
means 50 to rotate the permanent magnet 31A. As the permanent magnet 31A 
rotates, the closed door holding means 30A operates to attract the movable 
magnetic pole 39. In association with this, since the slider 4b also moves 
the sliding door 1A to its closing direction, the closed door holding 
means 30A fixed to the side wall 5 holds the sliding door 1A in the closed 
state thereof via the movable magnetic pole 39. Since the magnetic path of 
the closed door holding means 30A is closed with the movable magnetic pole 
39, the permanent magnet 31A is self-held not to rotate. 
As the slider 4b is moved in the opening direction within the gap X by the 
linear motor operated to open the sliding door 1A from the closed state 
thereof, the slider 4b, now allowed to move within the gap X of the 
coupling means 20, moves the attracting-and-releasing means 50 to the 
opening direction, though the closed door holding means 30A still keeps 
closing the sliding door 1A through the movable magnetic pole 39. Due to 
this movement, the slider 4b rotates the permanent magnet 31A through the 
attracting-and-releasing means 50 and the movement converting means 40, 
and the closed door holding means 30A releases the held movable magnetic 
pole 39, i.e., the closed sliding door 1A. Then, the sliding door 1A is 
fully opened through the coupling means 20 as the slider 4b further moves 
in the opening direction. In association with this, the 
attracting-and-releasing means 50 escapes from the attracted state and 
separates from the slider 4b, and the permanent magnet 31A is self-held to 
prepare for the next closing of the door with the attracting-and-releasing 
means 50. 
The operation for manually opening the closed doors 1A, 1B will be 
explained below. The slider 4b has a play space in which the slider 4b can 
move for the gap X in the opening direction even when the linear motor is 
not operated and the closed door holding means 30A keeps closing the 
sliding door 1A through the movable magnetic pole 39. Therefore, the 
permanent magnet 31A of the closed door holding means 30A is rotated to 
release the holding by the force for moving the slider 4b. The force for 
moving the slider 4b is enough to move the rack 41 or the movable frame 
43. By pulling each wire for the sliding door 1A or 1B, the movable frame 
43 for each sliding door is moved. Then, the sliding doors 1A, 1B may be 
opened manually by small operating force. 
It takes a time for the conventional door closing apparatus to open both 
sliding doors 1A and 1B in emergency, since two wires 62, 62 of the manual 
releasing means 60 should be manipulated to open the both sliding doors 1A 
and 1B. 
SUMMARY OF THE INVENTION 
In view of the foregoing, it is an object of the invention to provide a 
door closing apparatus on vehicle which facilitates simultaneously opening 
both of the sliding doors 1A, 1B manually simply by pulling a string of 
wire for manual release of the closed door holding means for both sliding 
doors. Specifically, a flat belt, V-shaped belt, rope, chain or timing 
belt may be used for the belt of the wrapping connector mechanism, and the 
belt pulleys which are suited for the adopted belt are preferably used in 
the invention. 
According to an aspect of the invention there is provided a door closing 
apparatus for closing sliding doors of a vehicle, which comprises: a 
support rail fixed to the vehicle's side wall; a pair of sliding doors 
hung on the support rail, the sliding doors being movable in opposite 
directions to each other; a pair of linear motors for driving the 
respective sliding doors, each of the linear motors including a slider; 
coupling means coupling with the respective sliding doors for gaps in the 
opening-and-closing direction of the respective sliding doors, each of the 
coupling means including a driving plate fixed to the slider and a passive 
plate fixed to the sliding door; movable magnetic poles fixed to the 
respective sliding doors; closed door holding means fixed to the side wall 
of the vehicle, each of the closed door holding means including a pair of 
pole shoes and a cylindrical permanent magnet sandwiched between the pole 
shoes, the permanent magnet being rotated for attracting or releasing the 
movable magnetic pole of the sliding door to hold or release the sliding 
door closed; attracting-and-releasing means for attracting and for 
releasing the respective sliders of the sliding doors immediately before 
the sliding doors are closed, the attracting-and-releasing means being 
disposed between the closed door holding means and the sliders; movement 
converting means, each including a movable frame movable linearly with 
respect to the side wall, for converting the linear movements of the 
attracting-and-releasing means to rotational movements of the permanent 
magnets through the movable frames; a wrapping connector mechanism 
including a pair of belt pulleys and a belt wound around the belt pulleys, 
the wrapping connector mechanism being arranged in parallel to the movable 
frames; at least one manual release wire, a terminal end thereof being 
connected to the belt's portion between the belt pulleys; two hook fixed 
to the belt or the terminal end of the at least one manual release wire, 
the hooks being made contact with the respective movable frames; and at 
least the belt being led through the movable frames' holes. 
Advantageously, the door closing apparatus further includes a touch sensor 
disposed on the closed doer holding means' plane, thereon the closed door 
holding means attracts the movable magnetic pole; and a portion disposed 
on the movable magnetic pole corresponding to the touch sensor's central 
portion, the portion being made of an elastic material and formed to be 
slightly convex. 
Advantageously, the door closing apparatus further includes a 
self-lubricating sheet interposed between the pole shoes and the permanent 
magnet of the closed door holding means. 
As the sliders of the linear motors for the sliding doors move in the 
closing direction, the coupling means move with gaps left behind to close 
the sliding doors and bring the attracting-and-releasing means to the 
state right before the attraction. As the sliding doors are further 
closed, the sliders drive the movement converting means through the 
attracting-and-releasing means to rotate the permanent magnets. As the 
permanent magnets rotate, the closed door holding means operate to attract 
the respective movable magnetic poles. In association with this, since the 
sliders also move the sliding doors to the closing directions thereof, the 
closed door holding means fixed to the side wall hold the respective 
sliding doors in the closed state thereof through the movable magnetic 
poles. 
As the sliders are moved in the opening direction within the gap by the 
linear motors operated to open the sliding doors from the closed state 
thereof, the sliders, now allowed to move within the gap of the coupling 
means, move the respective attracting-and-releasing means to the opening 
directions, though the closed door holding means still keep closing the 
sliding doors through the movable magnetic poles. Due to these movements, 
the sliders rotate the permanent magnets via the attracting-and-releasing 
means and the movement converting means, and the closed door holding means 
release the held movable magnetic poles, i.e., the closed sliding doors. 
Then, the sliding doors are fully opened through the coupling means as the 
sliders further move in the opening directions. In association with this, 
the attracting-and-releasing means separate from the sliders, and the 
permanent magnets are self-held to prepare for the next closing of the 
doors with the attracting-and-releasing means. 
The sliders have respective play spaces, i.e. the gaps, in which the 
sliders can move in the opening direction even when the linear motors are 
not operated, and the closed door holding means keep closing the sliding 
door through the movable magnetic poles. Therefore, the permanent magnets 
of the closed door holding means are rotated to release the holding by the 
force for moving the sliders. The force for moving the sliders is enough 
to move the racks or the movable frames. Thereafter, the sliding doors may 
be opened manually by small operating force. 
By pulling a string of manual release wire, the belt fixed to the wire 
moves with the belt pulleys, and two hooks contact and move the respective 
movable frames to the opening directions thereof. Due to these movements, 
the permanent magnets rotate, through the racks and gears, to release the 
holding of the closed doors. Now, the sliding doors can be opened 
manually. 
Even if the touching portions of the respective touch sensors, disposed on 
the respective planes where the closed door holding means are attracted to 
the respective movable magnetic poles, are formed to be convex stripes due 
to the technical requirements for manufacturing, slightly convex portions, 
made of an elastic material, are disposed on the movable magnetic poles 
corresponding to the respective centers of the touch sensors. Due to this 
configuration, the attitudes of the movable magnetic poles are controlled 
until the slightly convex portions secures the contact thereof with the 
respective touch sensors, even when the movable magnetic poles are slant 
to the respective convex stripes. Thus, linear motors keep closing the 
sliding doors until the sliding doors are completely shut by the 
sufficient holding force. 
By the provision of the self-lubricating sheets, the pole shoes and the 
permanent magnet may survive the many rotating cycles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will be explained hereinafter with reference to the 
drawing figures which illustrate the preferred embodiments of the 
invention. FIG. 1 is a cross section of an embodiment of a door closing 
apparatus according to the present invention. This figure shows a B--B 
cross section of FIG. 2 which is a C--C cross section of FIG. 1. FIG. 3 is 
a D--D cross section of FIG. 1. In these figures, the like parts with 
those of the prior art shown in FIGS. 4 and 5 are designated by the like 
reference numerals and their explanation will be omitted. 
Referring now to FIGS. 1, 2, and 3, the like parts with those of FIGS. 4 
and 5 will be explained at first. A left sliding door 1A and a right 
sliding door 1B are hung with a plurality of door sheaves (not shown, but 
similar to those of the prior art) on a supporting rail (not shown, but 
similar to that of the prior art) extending horizontally along a side wall 
5 of the vehicle. The sliding doors 1A and 1B open and close a passenger 
entrance of the vehicle. A stopper 74 is fixed to the side wall 5. A 
coupling means 20 for coupling a slider 4b of a linear motor and the 
sliding door 1A or 1B includes a driving plate 21 fixed to the slider 4b 
and a passive plate 22 fixed to the sliding door 1A or 1B. The sliding 
door 1A or 1B is opened and closed with a gap X between the plates 21 and 
22 in the opening-and-closing direction. 
Movable magnetic poles 39, 39 are fixed via respective adjustable joints 
38, 38 to the respective sliding doors 1A, 1B. Closed door holding means 
30A, 30B are fixed to the side wall 5 facing opposite to the magnetic 
poles 39. 39. The closed door holding means 30A or 30B includes a 
cylindrical permanent magnet 31A or 31B which magnetically fixes opposed 
facing N and S poles in the radial direction thereof and a pair of pole 
shoes 32A or 32B surrounding the N and S poles. Each of the pole shoes has 
a non-magnetic portion at the end thereof. In the state shown in the 
figures, the closed door holding means 30A, 30B, with the internal 
magnetic paths thereof closed, attract the respective movable magnetic 
poles 39, 39. When the permanent magnets 31A, 31B rotate by 90 degrees of 
angle from the illustrated positions, the internal magnetic paths of the 
closed door holding means 30A, 30B are open not to attract the movable 
magnetic poles 39, 39. Thus, the closed door holding means 30A, 30B 
release and hold the closed state of the sliding doors 1A, 1B by a quarter 
turn of permanent magnets 31A, 31B. 
Gears 42A and 42B which couple with respective racks 41A and 41B are fixed 
to the permanent magnets 31A and 31B of the closed door holding means 30A 
and 30B. The rack 41A or 41B and the gear 42A or 42B constitute a movement 
converting means 40A or 40B for converting a linear movement to a 
rotational movement. The movement converting means 40A, 40B may comprise a 
link mechanism. The rack 41A and 41B are fixed to respective movable 
frames 43A and 43B which move on a slide rail 5a fixed to the side wall 5 
in the opening-and-closing direction of the sliding doors, and rotate the 
respective permanent magnets 31A and 31B by 90 degrees of angle. 
An attracting-and-releasing means 50 is disposed between the slider 4b and 
the movable frame 43A or 43B. The attracting-and-releasing means 50 
includes an adjustable joint 51 and a magnet 52 for attracting the 
adjustable joint 51. The adjustable joint 51 is attracted to the magnet 52 
when the adjustable joint 51 is positioned, e.g., within the gap X from 
the magnet 52, and the adjustable joint 51 is not attracted to the magnet 
52 as far as the adjustable joint 51 is positioned for more than the gap X 
away from the magnet 52. 
As a specific feature of the embodiment, a wrapping connector mechanism 80 
which includes a pair of belt pulleys 81, 81 and a belt 82 wound around 
the pulleys 81, 81 is arranged in parallel to a pair of the movable frames 
43A, 43B. The belt 82 is connected, at a portion thereof between the 
pulleys 81, 81, to a terminal end of a manual release wire 83A, which is 
fixed to a hook 84A. The hook 84A is made contact to a portion 43Aa of the 
movable frame 43A, and the belt 82 and the manual release wire 83A are led 
through a hole of the movable frame 43A. In the same manner as described 
above, the belt 82 is connected, at another portion thereof between the 
pulleys 81, 81, to a terminal end of a manual release wire 83B, which is 
fixed to another hook 84B. The hook 84B is made contact to a portion 43Ba 
of the movable frame 43B, and the belt 82 and the manual release wire 83B 
are led through a hole of the movable frame 43B. The manual release wire 
83A is led through a sheath 85A fixed to a fitting of the side wall 5, and 
the terminal end of the manual release wire 83A is connected to a manual 
release lever 86A. The manual release wire 83B is led through another 
sheath 85B fixed to another fitting on the side wall 5, and the terminal 
end of the manual release wire 83B is connected to another not shown 
manual release lever. It is sufficient to provide either one of the manual 
release levers. Alternatively, one of the manual release levers may be 
arranged inside the vehicle and another one outside the vehicle. The hook 
84A which contacts with the movable frame 43A fixes both the belt 82 and 
the terminal end of the manual release wire 83A. Alternatively, the belt 
82 and the terminal end of the manual release wire 83A may be fixed to 
another fitting. In this alternative, the fitting should be arranged so as 
not to run onto the pulley 81 over the entire stroke of the rack 41A 
during pulling the manual release wire 83A. The situations are the same 
for the hook 84B. 
As another specific feature specific feature of the embodiment, touch 
sensors 71, 71, each thereof having a convex stripe 71a in the touching 
portion thereof, are disposed on respective planes where the closed door 
holding means 30A, 30B are attracted to the respective movable magnetic 
poles 39, 39. And, a slightly convex portion 87, made of an elastic 
material, is disposed on the movable magnetic pole 39 corresponding to the 
center of the touch sensor 71. Moreover, a self-lubricating sheet 88 is 
interposed between the pole shoes 32A, 32A or 32B, 32B of the closed door 
holding means 30A or 30B and the permanent magnet 31A or 31B. 
The operation of the foregoing embodiment will be explained below. As the 
sliders 4b, 4b of the linear motors for the sliding doors 1A, 1B move in 
the closing direction, the coupling means 20, 20 move, with the gap X left 
behind, to close the sliding doors 1A, 1B and bring the 
attracting-and-releasing means 50, 50 to the state right before the 
attraction. As the sliding doors 1A, 1B are further closed, the sliders 
drive the movement converting means 40A, 40B through the 
attracting-and-releasing means 50, 50 to rotate the permanent magnets 31A, 
31B. As the permanent magnets 31A, 31B rotate, the closed door holding 
means 30A, 30B operate to attract the respective movable magnetic poles 
39, 39. In association with this, since the sliders 4b, 4b also move the 
sliding doors 1A, 1B to the closing directions thereof, the closed door 
holding means 30A, 30B fixed to the side wall 5 hold the respective 
sliding doors 1A, 1B in the closed sate thereof through the movable 
magnetic poles 39, 39. 
As the sliders 4b, 4b are moved in the opening direction within the gap X 
by the linear motors operated to open the sliding doors 1A, 1B from the 
closed state thereof, the sliders, now allowed to move within the gap X of 
the coupling means 20, 20, move the respective attracting-and-releasing 
means 50, 50 to the opening directions, though the closed door holding 
means 30A 30A still keep closing the sliding doors 1A, 1B through the 
movable magnetic poles 39, 39. Due to these movements, the sliders 4b, 4b 
rotate the permanent magnets 31A, 31B through the attracting-and-releasing 
means 50, 50 and the movement converting means 40, 40, and the closed door 
holding means 30A, 30B release the held movable magnetic poles 39, 39, 
i.e., the closed sliding doors 1A, 1B. Then, the sliding doors 1A, 1B are 
fully opened through the coupling means 20, 20 as the sliders 4b, 4b 
further move in the opening directions. In association with this, the 
attracting and releasing means 50, 50 separate from the sliders 4b, 4b, 
and the permanent magnets 31A, 31B are self-held to prepare for the next 
closing of the doors with the attracting-and-releasing means. 
The operation for manually opening the closed doors 1A, 1B will be 
explained below. The sliders 4b, 4b have respective play spaces, i.e. the 
gaps X, X in which the sliders 4b, 4b can move in the opening direction 
even when the linear motors are not operated, and the closed door holding 
means 30A, 30B keep closing the sliding door 1A, 1B through the movable 
magnetic poles 39, 39. Therefore, the permanent magnets 31A, 31B of the 
closed door holding means 30A, 30B are rotated to release the holding by 
the force for moving the sliders 4b, 4b. The force for moving the sliders 
4b, 4b is enough to move the racks 41A, 41B or the movable frames 43A, 
43B. Thereafter, the sliding doors 1A, 1B may be opened manually by small 
operating force. 
By pulling a string of manual release wire 83A or 83B, the belt fixed to 
the wire moves with the belt pulleys 81, 81, and two hooks 84A, 84B 
contact and move the respective movable frames 43A, 43B to the opening 
directions thereof. Due to these movements, the permanent magnets 31A, 31B 
rotate, through the racks 41A, 41B and gears 42A, 42B, to release the 
holding of the closed doors 1A, 1B. Now, the sliding doors 1A, 1B can be 
opened manually. 
Even if the touching portions of the respective touch sensors 71, 71, 
disposed on the respective planes where the closed door holding means 30A, 
30B are attracted to the respective movable magnetic poles 39, 39, are 
formed to be convex stripes 71a, 71a due to the technical requirements for 
manufacturing, slightly convex portions 87, 87, made of an elastic 
material, are disposed on the movable magnetic poles 39. 39 corresponding 
to the respective centers of the touch sensors 71, 71. Due to this 
configuration, the attitudes of the movable magnetic poles 39, 39 are 
controlled until the slightly convex portions 87, 87 secures the contact 
thereof with the respective touch sensors 71, 71, even when the movable 
magnetic poles 39, 39 are slant to the respective convex stripes 71a, 71a. 
Thus, linear motors keep closing the sliding doors 1A, 1B until the 
sliding doors 1A, 1B are completely shut by the sufficient holding force. 
By the provision of the self-lubricating sheets 88 and 88, the pole shoes 
32A, 32B and the permanent magnets 31A, 31B may survive the many rotating 
cycles. 
As explained above, by pulling one of the manual release wires, the belt 
fixed to the pulled wire moves with the belt pulleys, and two hooks 
contact and move the respective movable frames to the opening directions 
thereof. Due to these movements, the permanent magnets rotate, through the 
movement converting means, to release the holding of the closed doors. 
Thus, the sliding doors can be opened manually. 
Even when the touching portions of the respective touch sensors, disposed 
on respective planes where the closed door holding means are attracted to 
the respective movable magnetic poles, are formed to be convex stripes due 
to the technical requirements for manufacturing, slightly convex portions, 
made of an elastic material, are disposed on the movable magnetic poles 
corresponding to the respective centers of the touch sensors. Due to this 
configuration, the attitudes of the movable magnetic poles are controlled 
until the slightly convex portions secures the contact thereof with the 
respective touch sensors, even when the movable magnetic poles are slant 
to the respective convex stripes. Thus, linear motors keep closing the 
sliding doors until the sliding doors are completely shut by the 
sufficient holding force. By the provision of the self-lubricating sheets, 
the pole shoes and the permanent magnet may survive the many rotating 
cycles.