Anchoring apparatus for wheeled chair

An anchoring apparatus for a wheeled chair mainly composed of a movable frame assembled with a seat frame structure of the wheeled chair to be movable in a vertical direction, a hydraulic damper assembled with the seat frame structure for biasing the movable frame upwardly to retain the movable frame in a lifted position in a released condition of the anchoring apparatus, a foot pedal mechanism having a foot pedal assembled with the seat frame structure of the wheeled chair to lower the movable frame when depressed by an attendant, a locking mechanism mounted on the movable frame to be locked by engagement with a stationary element fixed to a floor when the movable frame has been lowered by depression of the foot pedal, and a releasing mechanism assembled with the seat frame structure of the wheeled chair, the releasing mechanism having an operation lever mounted on a back frame structure of the wheeled chair and operatively connected to the locking mechanism to release engagement of the locking mechanism with the stationary element when operated by the attendant.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an anchoring apparatus for a wheeled chair 
which is suitable for anchoring the wheeled chair on a floor such as the 
floor of a vehicle compartment. 
2. Description of the Prior Art 
Various anchoring apparatus for a wheeled chair have been proposed for 
anchoring the wheeled chair on the floor of a vehicle compartment or the 
like while a person is seated on the wheeled chair. Although the most 
important function of such anchoring apparatus is to securely and firmly 
anchor the wheeled chair on the floor, the following are also important 
requirements. Namely, operation by an attendant for locking and releasing 
the wheeled chair must be simple and easy, the structure of the anchoring 
apparatus should not be complex, and the wheeled chair can be anchored at 
desired places. To meet these requirements, an improved anchoring 
apparatus for wheeled chairs has been proposed in Japanese Utility Model 
Laid-open Publication No. 2-141563. 
However, since the proposed anchoring apparatus is designed to be installed 
on a floor at which a wheeled chair is to be anchored, the wheeled chair 
can be anchored only at a specific place where the anchoring apparatus is 
installed. In a case in which the wheeled chair must be anchored at 
various places, the anchoring apparatus must be installed at the 
respective places. Accordingly, the conventional anchoring apparatus is 
not economical in view of costs for the anchoring apparatus and 
installation thereof. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide an improved anchoring 
apparatus for a wheeled chair capable of anchoring the wheeled chair at 
various places on a floor in a simple manner. 
Another object of the present invention is to provide an improved anchoring 
apparatus for a wheeled chair which can be assembled with the wheeled 
chair in a simple construction. 
A further object of the present invention is to provide an improved 
anchoring apparatus for a wheeled chair which is economically advantageous 
in terms of installation cost. 
According to the present invention, the objects are accomplished by 
providing an anchoring apparatus for a wheeled chair, which comprises a 
movable frame assembled with a seat frame structure of the wheeled chair 
to be movable in a vertical direction; means for biasing the movable frame 
upwardly to retain the movable frame in a lifted position in a released 
condition of the anchoring apparatus; a foot pedal mechanism having a foot 
pedal assembled with the seat frame structure of the wheeled chair to 
lower the movable frame when depressed by an attendant; a locking 
mechanism mounted on the movable frame to be locked by engagement with a 
stationary element fixed to a floor when the movable frame has been 
lowered by depression of the foot pedal; and a releasing mechanism 
assembled with the seat frame structure of the wheeled chair, the 
releasing mechanism including an operation lever mounted on a back frame 
structure of the wheeled chair and operatively connected to the locking 
mechanism to release engagement of the locking mechanism with the 
stationary element when operated by the attendant. 
In a practical embodiment of the present invention, it is preferable that a 
support frame is mounted on the seat frame structure of the wheeled chair 
and located above the movable frame, wherein a link mechanism is assembled 
with the support frame and the movable frame to carry the movable frame 
thereon for vertical movement. It is also preferable that the support 
frame has a pair of laterally spaced parallel first side members each of 
which is formed with an elongated guide slot at a position adjacent to its 
one end, and the movable frame has a pair of laterally spaced parallel 
second side members each of which is formed with an elongated guide slot 
at a position adjacent to its one end, wherein the link mechanism includes 
a pair of laterally spaced first link members pivoted at their one ends to 
the other ends of the first side members and at their other ends to first 
support pins slidably engaged with the guide slots of the second side 
members and a pair of laterally spaced second link members pivoted at 
their one ends to the other ends of the second side members and at their 
other ends to second support pins slidably engaged with the guide slots of 
the first side members, the first link members being pivoted to the second 
link members at their central portions, respectively. 
In such an arrangement of the link mechanism, it is preferable that the 
biasing means comprises a pair of laterally spaced dampers each having a 
cylinder and a piston rod, the cylinders being pivoted to the other ends 
of the first side members, while the piston rods being pivoted to the 
first support pins, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
An embodiment of the present invention will now be described in detail with 
reference to the drawings, in which FIGS. 1 and 2 schematically illustrate 
a wheeled chair equipped with an anchoring apparatus 30 according to the 
present invention, FIGS. 3 and 4 illustrate the anchoring apparatus 30 in 
relation to a seat frame structure 11 of the wheeled chair, and FIGS. 5 
and 6 illustrate the mode of operation of locking mechanisms 35, 36 of the 
anchoring apparatus 30. 
The wheeled chair is mainly composed of the seat frame structure 11, a back 
frame structure 12, a pair of rear wheels 21, a pair of front wheels 22, a 
seat cushion 23 and a seat back 24. The anchoring apparatus 30 is located 
under the seat frame structure 11 and assembled therewith. The seat frame 
structure 11 is composed of upper and lower frames 11a and 11b which are 
spaced in a vertical direction and unitedly connected with each other. The 
seat cushion 23 is detachably placed on and fixed to the upper frame 11a. 
The back frame structure 12 is composed of left-hand and right-hand 
upstanding frame rods 12a and 12b which are secured at their lower ends to 
the rear end of upper frame 11a and inclined backwardly. The upstanding 
frame rods 12a and 12b are integrally formed at their upper ends with 
horizontal grip portions 12c and 12d which are adapted as an operation 
portion of an attendant. The seat back 24 is detachably fixed to the back 
frame structure 12. The seat frame structure 11 is carried at Its rear end 
by means of the rear wheels 21 and at its front end portions by means of 
the front wheels 22. In addition, the seat frame structure 11 is provided 
at its front end with a pair of foot-rests 13a and 13b. 
As shown in FIGS. 3 and 4, the anchoring apparatus 30 is composed of a pair 
of laterally spaced first link members 31a, 31a, a pair of laterally 
spaced second link members 31b, 31b, an upper support frame 32, a lower 
movable frame 33, a pair of laterally spaced hydraulic dampers 34 a pair 
of laterally spaced side locking mechanisms 35, 35, a front locking 
mechanism 36, a foot pedal assembly 37 and a releasing mechanism 38. The 
upper support frame 32 is formed to correspond in configuration with the 
lower frame 11b of the seat frame structure 11 and is fixedly mounted on 
the lower frame 11b. (see FIG. 2) As shown in FIGS. 3 and 4, the upper 
support frame 32 has a pair of laterally spaced parallel side members 32a 
each of which is formed with an elongated guide slot 32b in a fore-and-aft 
direction at a forwardly offset position thereof. The lower movable frame 
33 is formed slightly smaller in size than the upper support frame 32. The 
lower movable frame 33 is located under the upper support frame 32 and is 
connected to the side members 32a of upper support frame 32 by means of 
the link members 31a and 31b. The lower movable frame 33 has a pair of 
laterally spaced parallel side members 33a each of which is formed with an 
elongated guide slot 33b in a fore-and-aft direction at a forwardly offset 
position thereof. 
The pair of first link members 31a, 31a are pivoted at their rear ends to 
the rear ends of upper side members 32a, 32a by means of support pins 39a, 
39a and are rotatably carried on support pins 39b, 39b at their front 
ends. The support pins 39b, 39b are slidably engaged with the guide slots 
33b, 33b of lower side members 33a, 33a for movement in the fore-and-aft 
direction. The pair of second link members 31b, 31b are pivoted at their 
rear ends to the rear ends of lower side members 33a, 33a by means of 
support pins 39c, 39c and are rotatably carried on support pins 39d, 39d 
at their front ends. The support pins 39d, 39d are slidably engaged with 
the guide slots 32b, 32b of upper side members 32a, 32a for movement In 
the fore-and-aft direction. In addition, the first link members 31a, 31a 
are pivotally connected to the second link members 31b, 31b at their 
central portions, respectively. 
Each of the hydraulic dampers 34, 34 has a cylinder 34a and a piston rod 
34b. As shown in FIG. 4, the cylinders 34a are rotatably supported on the 
support pins 39a, 39a respectively at their rear ends to be movable in a 
vertical direction. The piston rods 34b, 34b are rotatably carried by the 
support pins 39d, 39d respectively at their front ends to be movable in a 
vertical direction. In the above arrangement of the hydraulic dampers 34, 
34, the support pins 39d, 39d are maintained in engagement with the front 
ends of guide slots 32b, 32b under the biasing force of dampers 34, 34 so 
that the lower movable frame 33 is retained in a lifted position by means 
of the link members 31a and 31b as shown in FIG. 3. When the lower movable 
frame 33 is lowered by a depression force applied thereto, the support 
pins 39d, 39d are moved rearwardly against the biasing force of dampers 
34, 34. 
The locking mechanisms 35 and 36 are substantially the same in 
construction. As shown in FIGS. 1 and 3, the pair of side locking 
mechanisms 35, 35 are mounted on the side members 33a, 33a of lower 
movable frame 33 at their inside faces, while the front locking mechanism 
36 is mounted on a front lateral member 33c of lower movable frame 33 at 
its inside face. As shown in FIGS. 5 and 6, the locking mechanisms 35, 36 
are composed of base plates 35a, 36a respectively secured to the lower 
movable frame 33, detent plates 35b, 36b respectively pivoted to the base 
plates 35a, 36a by means of support pins 35c, 36e, locking levers 35c, 36c 
respectively pivoted to the base plates 35a, 36a by means of support pins 
35f, 36f and coil springs 35d, 36d respectively engaged at their opposite 
ends with the detent plates 35b, 36b and locking levers 35c, 36c. 
The detent plates 35b, 36b are formed with hook portions 35.sub.b1, 
36.sub.b1 and recessed portions 35.sub.b2, 36.sub.b2, respectively. The 
locking levers 35c, 36c are respectively formed with protrusions 
35.sub.c1, 36.sub.c1 to be engaged with the recessed portions 35.sub.b2, 
36.sub.b2 of detent plates 35, 36. The coil springs 35d, 36d are engaged 
at their one ends with each upper end of detent plates 35b, 36b and at 
their other ends with each upper end of locking levers 35c, 36c to bias 
the detent plates 35b, 36b and locking levers 35c, 36c in opposite 
directions to one another. Thus, in each released condition of the locking 
mechanisms 35, 36, the hook portions 35.sub.b1, 36.sub.b1 of detent plates 
35b, 36b are directed to open downwardly under the biasing force of coil 
springs 35d, 36d, and the protrusions 35.sub.c1, 36.sub.c1 of locking 
levers 35c, 36c are positioned apart from the recessed portions 35.sub.b2, 
36.sub.b2 of detent plates 35b, 36b as shown in FIG. 5. When the hook 
portions 35.sub.b1, 36.sub.b1 of detent plates 35b, 36b are brought into 
engagement with strikers 42, 43 fixedly mounted on the floor 41 of a 
vehicle compartment as shown in FIGS. 3 and 6, the protrusions 35.sub.c1, 
36.sub.c1 of locking levers 35c, 36c are engaged with the recessed 
portions 35.sub.b2, 36.sub.b2 of detent plates 35b, 36b and maintained in 
engagement therewith under the biasing force of coil springs 35d, 36d in 
each locked condition of the locking mechanisms 35, 36. 
As shown in FIGS. 3 and 4, the foot pedal mechanism 37 includes a foot 
pedal 37a fixed to the rear end of a pedal arm 37b. As shown in FIG. 4, 
the upper support frame 32 is provided with a center beam 32c which 
extends in the fore-and-aft direction at the centeral portion of support 
frame 32. A link member 32d is rotatably connected at its upper end to an 
intermediate portion of center beam 32c by means of a support pin 39g and 
at its lower end to the front end of pedal arm 37b to be swingable in a 
vertical direction. The pedal arm 37b is rotatably carried on an upright 
bracket 33e at Its intermediate portion by means of a support pin 39h to 
be swingable In a vertical direction. The upright bracket 33e is fixedly 
mounted on a rear lateral member 33d of the lower movable frame 33. 
As shown in FIGS. 1 and 4, the releasing mechanism 38 includes a swing arm 
38a, an operation lever 38b, a first operation wire 38c and a second 
operation wire 38c. The swing arm 38a is pivoted at its one end to a 
lateral bracket (not shown) by means of a support pin 391 to be swingable 
in the fore-and aft direction. The lateral bracket is fixedly mounted on 
the center beam 32c for support of the swing arm 38a. As shown in FIG. 1, 
the operation lever 38b is mounted on the grip portion 12d of the 
right-hand back frame 12b to be operated by an attendant. The first 
operation wire 38c is connected at its one end to the operation lever 38b 
and at its other end to the movable end of swing arm 38a, while the second 
operation wire 38d is connected at its one end to an intermediate portion 
of swing arm 38a and at its other end to the respective locking levers 35 
c, 36c of the locking mechanisms 35, 36, as shown in FIG. 5. 
Assuming that the wheeled chair is in an unlocked condition, the lower 
movable frame 33 is retained in the lifted position under the biasing 
force of dampers 34, 34, as shown in FIGS. 1 and 2. In such a condition, 
the locking mechanisms 35, 36 are maintained in their unlocked conditions 
as shown in FIG. 5 to permit free movement of the wheeled chair, and the 
hook portions 35.sub.b1, 36.sub.b1 of detent plates 35b, 36b are directed 
to open downwardly. When the attendant wishes to anchor the wheeled chair 
on the floor 41 of the vehicle compartment, the wheeled chair is placed at 
a predetermined position so that the locking mechanisms 35, 36 are located 
above the strikers 42, 43 on the floor. When the foot pedal 37a is 
depressed by the attendant, the lower movable frame 33 is lowered by 
downward movement of the pedal arm 37b against the biasing force of 
dampers 34, 34 to bring the detent plates 35b, 36b of the locking 
mechanisms 35, 36 into engagement with the strikers 42, 43 at their hook 
portions 35.sub.b1, 36.sub.b1. In this instance, as shown in FIG. 6, the 
detent plates 35b, 36b are rotated clockwisely by abutment with the 
strikers 42, 43 against the biasing force of coil springs 35d, 36d, while 
the locking levers 35c, 36c are rotated clockwisely due to the action of 
coil springs 35d, 36d. As a result, the protrusions 35.sub.c1, 36.sub.c1 
of locking levers 35c, 36c are engaged with the recessed portions 
35.sub.b2, 36.sub.b2 of detent plates 35b, 36b and maintained in 
engagement therewith under the biasing force or coil springs 35d, 36d to 
prohibit rotation of the detent plates 35b, 36b and locking levers 35c, 
36c. Thus, the detent plates 35b, 36b are locked by engagement with the 
strikers 42, 43 to securely and firmly anchor the wheeled chair on the 
floor 41. 
When it is desired to release the wheeled chair from the anchored 
condition, the operation lever 38b of the releasing mechanism 38 is 
operated by the attendant so that the first operation wire 38c is pulled 
to rotate the swing arm 38a backwardly. In turn, the second operation wire 
38d is pulled by backward rotation of the swing arm 38a to rotate the 
locking levers 35c, 36c of the locking mechanisms 35, 36 
counterclockwisely in FIG. 6. As a result, the protrusions 35.sub.c1, 
36.sub.c1 of locking levers 35c, 36c are disengaged from the recessed 
portions 35.sub.b2, 36.sub.b2 of detent plates 35b, 36b, and the detent 
plates 35b, 36b are rotated counterclockwisely by the biasing force of 
coil springs 35d, 36d to release the hook portions 35.sub.b1, 36.sub.b1 of 
detent plates 35b, 36b from the strikers 42, 43. After the detent plates 
35b, 36b are released from the strikers 42, 43, the lower movable frame 33 
is lifted by the biasing force of dampers 34, 34, and the locking 
mechanisms 35, 36 are lifted with the lower movable frame 33 to release 
the wheeled chair from the floor 41 so as to permit free movement of the 
wheeled chair. 
From the above description, it will be understood that with the anchoring 
apparatus 30 according to the present invention. the wheeled chair can be 
securely and firmly anchored to the floor by depression of the foot pedal 
37 and can be released from the floor by operation of the operation lever 
38b of the releasing mechanism 38. It will be also understood that since 
the anchoring apparatus 30 is assembled with the wheeled chair, the 
wheeled chair can be anchored at any places where the strikers 42, 43 are 
provided for engagement with the locking mechanisms 35, 36. As the 
strikers 42, 43 are simple in construction, the anchoring apparatus 
according to the present invention is economically advantageous in terms 
of installation cost even in a case in which many strikers are provided at 
various places.