[0001] This invention relates to a shock absorber and, more particularly, to a shock absorber
for use in a pedal bin to reduce the force with which the lid of the bin is returned
to the closed condition during use.
[0002] Pedal bins are found in many different locations and have a particular usefulness
ina hospital environment where a lid is required on the bin to keep any material in
the bin isolated from the patients in the hospital. Pedal bins allow the operator
to open the lid of the bin without having to manually operate the lid. This is particulary
useful when the operator is carrying waste to be put into the bin and does not have
a free hand.
[0003] The bins are operated by a pedal at the foot of the bin which is generally depressed
inorder to raise the lid of the bin. Once material has been placed into the bin, the
pedal is released thereby allowing the lid to fall back onto the bin under the force
of gravity. Whilst this ensures that the bin is closed securely, the noise generated
from such an action can cause a disturbance. This is especially so where a number
of such bins are provided in one room, for example in a hospital. Here it is imperative
to ensure that the patients are not disturbed more than is necessary.
[0004] It is an object of the present invention to provide a shock absorber for a pedal
bin which is both efficient and quiet in closing the lid of a bin after use, thereby
overcoming or at least mitigating the disadvantages of the known pedal bins.
[0005] According to one aspect of the present invention there is provided a shock absorber
adapted for use on a pedal bin in which the lid of the pedal bin is opened and closed
by an actuating member, the shock absorber comprising damping means connected to the
actuating means to limit the speed of movement of the actuating means when the lid
of the bin is opened or closed.
[0006] Preferably, the shock absorber further comprises a body which is adapted to be mounted
on the bin adjacent to the actuating means of the bin, the damping means being mounted
within the body.
[0007] Advantageously, the damping means comprises bellows mounted which may expand or retract
within the body.
[0008] Conveniently, means are provided to connect the bellows to the actuating member of
the bin.
[0009] Advantageously, the connecting means comprises a planar member, one end of which
is provided with a recess to receive the actuating member and the other end of which
is connected to the leading end of the bellows.
[0010] Preferably also, the recess is defined between two arms of the planar member and
means are provided to alter the distance between the two arms thereby altering the
size of the recess to allow the connecting means to be securely affixed to the actuating
means of the bin.
[0011] Advantageously, the body of the shock absorber is provided with a longitudinal slot
along at least part of the length thereof, though which the planar member extends
as the bellows are expanded and retracted within the body.
[0012] Conveniently, the body is provided with an end cap closing the end of the body remote
from the planar member.
[0013] Advantageously, the end cap comprises an integrally formed hollow boss which extends
into the body and is received within the free end of the bellows.
[0014] Preferably also, an aperture is formed in outer surface of the end cap allowing air
to be drawn into the hollow boss.
[0015] Conveniently, a weight is provided within the boss, the weight being moveable between
a position wherein the aperture in the end cap is closed by the weight and a position
where the weight is lifted free of the aperture to allow air to be drawn into the
boss.
[0016] Advantageously, a limit stop is mounted on the boss to limit the movement of the
weight between the two extreme positions.
[0017] Preferably, the body is formed of a rigid plastics material.
[0018] Preferably also, the bellows are formed of a resilient plastics material.
[0019] One embodiment of the present invention will now be described with reference to the
accompanying drawings in which:
Figure 1 is a schematic side view of a pedal bin with a shock absorber according to one aspect
of the present invention mounted thereon;
Figure 1a is a schematic rear view of the bin of Figure 1;
Figure 2 is an exploded side view of the shock absorber of Figure 1;
Figure 3 is a schematic side view of the shock absorber of Figure 1 when the lid of the bin
is in a closed condition, and
Figure 3a is an enlarged view of the shock absorber as shown in Figure 3;
Figure 4 is a schematic side view of the shock absorber of Figure 1 when the lid of the bin
is in an opened condition.
[0020] Turning now to the Figures there is shown in Figure 1 a pedal bin generally referred
to as
1. The pedal bin comprises a hollow body
2 with an opening
3 at one end which may be adapted to receive a waste receptacle such as a plastics
waste bag for rubbish (not shown). The bin may be formed of a moulded plastics material.
[0021] The bin is provided with a hinged door
4 at the front thereof. This allows access to the bag when full, to allow the bag to
be removed from the bin and a new bag to be mounted within the body of the bin. The
door is hinged
5 at one side to the body. A door knob
6 is mounted on the door approximately mid-way between the top and bottom of the door
adjacent the edge remote from the hinges
5.
[0022] The bin
1 is provided with a lid
7 which covers the opening
3 in the body. The lid extends
7a beyond the rear of the bin and has a downward projecting lip
8 at the rear edge. The lip is extended
8a, 8b around the sides of the lid which extend beyond the rear of the bin. An aperture
9 is provided through the lip at each side of the lid.
[0023] A pair of generally triangular flanges
10 extend upward from the rear of the bin
1. The flanges are mounted to the bin adjacent the top edge and extend outwardly from
the bin to a position level with the top edge of the bin and adjacent to the end of
the lid
7.
[0024] The flanges
10 are each provided with an aperture
11 which is of a similar size to the aperture
9 in the lip of the lid. A mounting pin
12 extends through the apertures in the flanges and the lip of the lid to hingedly connect
the lid
7 to the bin
1.
[0025] A handle
13 is provided adjacent the rear of the lid of the bin, between the flanges
10.
[0026] At the base of the bin, the pedal
14 comprises a substantially rectangular plate
15 which is mounted underneath the bin. The front of the plate extends beyond the front
of the bin. The plate is pivotally mounted to the underside of the bin on a pivot
pin
16 which is retained in two apertures
17 in the sides of the lower section of the bin.
[0027] At the rear of the bin a wheel
18 is mounted at either side to enable the bin to be tilted back onto the wheels to
allow the bin to be easily moved from one location to another.
[0028] An actuating rod
19 is mounted at the rear of the bin. The rod is centrally located between the wheels
18 at the base of the bin and extends between the rear of the rectangular plate
15 and the underside of the lid
7 between the flanges
10.
[0029] A shock absorber
20 according to one aspect of the present invention is mounted between the base of the
bin
1 and the actuating rod
19 as shown in Figure
1. The shock absorber comprises a circular shroud
21, open at both ends and provided with integrally formed mountings
22 at one end to allow the shroud to be mounted to the rear of the bin
1. The shroud may be formed of any suitable plastics material and may be formed a known
molding process.
[0030] A generally rectangular U-shaped slot
23 is provided in the shroud, the slot extending approximately three quarters of the
length of the shroud and off-set from the centre of the shroud, towards one of the
mountings
22 as shown in Figure
[0031] An end cap
24 is mounted in the lower end of the shroud
21 to close the lower side of the shroud. The end cap is generally circular and is of
a similar diameter to the diameter of the shroud itself.
[0032] A hollow boss
25 extends from the centre of the end cap and is adapted to be received within the shroud
21. The boss is generally circular in cross-section and is of slightly smaller diameter
than the end cap thereby defining a rim
26 on the end cap. The boss is frustoconical in configuration and has a circular aperture
27 in the centre. The underside of the endcap
24a is provided with an aperture
28 which connects the inner chamber of the end cap, within the boss
25 with the atmosphere.
[0033] A cylindrical spigot
29 is mounted within the chamber in the boss, the circumference of the spigot being
slightly smaller than the circumference of the aperture
27 in the boss thereby allowing the spigot to move freely within the aperture. The end
of the spigot within the boss is provided with a countersunk aperture and a rubber
insert (not shown) is mounted in the aperture. The spigot has a groove
30 around the circumference thereof adjacent to the end of the spigot remote from the
rubber insert.
[0034] A limit stop
31 is located adjacent to the spigot
29, the limit stop having a generally circular body
32 and a flat head
33, the head being received within the groove
30 in the body of the spigot. The head
33 of the limit stop is approximately a third of the height of the groove and therefore
allows the spigot
29 to move within the aperture in the boss between two extreme positions in which the
head of the limit stop contacts either the lower side of the groove or the upper side
of the groove.
[0035] Bellows
34 are mounted within the shroud
21 of the absorber. The bellows are formed of a light-weight, flexible plastics material.
The diameter of the bellows is slightly less than the internal diameter of the shroud
to allow the bellows to contract and expand within the shroud. The bellows are mounted
over the boss
25 of the end cap
24.
[0036] The end of the bellows
34 remote from the cap is provided with a circular aperture
35. An actuation member
36 of the absorber is mounted on the bellows. The actuation member comprises a bifurcated
body
37 having a generally circular end
38 with an aperture
39 corresponding in shape and size to the aperture
35 in the end of the bellows. A threaded bolt
40 passes through the aperture
39 in the body and the aperture
35 in the bellows and is retained in position by a threaded nut
41.
[0037] The other end of the body
37 is bifurcated to provide two arms
42,43. A generally circular collar
44 is integrally moulded with the body where the arms join on the body. The diameter
of the collar is slightly larger than the diameter of the actuating rod
19 to allow the actuating rod to be received in the collar.
[0038] An aperture
45 is provided through the end of each arm
42, 43 of the actuating member. A threaded bolt
46 is passed through the apertures and is retained within the apertures by a threaded
nut
47 at either end.
[0039] The shock absorber
20 is mounted at the base of the bin
1 at the rear in a recess
48. The end cap
24 is placed over the end of the shroud
21, the bellows
34 are mounted in the shroud over the cap and the actuating arm
36 is attached to the free end of the bellows.
[0040] The actuating rod
19 is then passed between the arms
42, 42 of the bifurcated actuating arm and is received in the collar
44. The threaded nuts
47 are then tightened on the threaded bolt
46 to connect the shock absorber to the actuating rod.
[0041] When the lid
7 of the bin is in the closed condition, the bellows
34 are in the compressed condition as shown in Figure of the drawings. In this position
the actuating member
36 is at the lower position within the slot
22 in the shroud
21.
[0042] When the lid of the bin is to be lifted to place rubbish into the receptacle within
the bin, the pedal
15 of the bin is depressed which causes the pedal to hinge around the mounting pin
16. As the front of the pedal is lowered, the rear of the pedal is raised thereby lifting
the actuating rod
19. As the actuating rod is lifted, the end of the actuating rod contacts the underside
of the rear of the lid
7a of the bin and lifts the lid clear of the top edge of the bin allowing access to
the receptacle.
[0043] As the actuating rod
19 is lifted to lift the lid
7 of the bin, the actuating member
36 moves upwards together with the rod, through the slot
22 in the shroud
21 and pulls the bellows
34 upwards within the shroud
21.
[0044] As the bellows expand within the shroud, the spigot
29 is sucked from its seat within the boss
25 and is lifted until the head
33 of the limit stop contacts the lower edge of the groove
30 in the spigot, thereby preventing the spigot from lifting further. Whilst the spigot
is lifted free from the aperture
28 in the end cap
25, air is drawn in through the aperture and around the spigot into the bellows.
[0045] The lid
7 of the bin is held in the open condition whilst the operator's foot is on the pedal
15. In this condition, the actuating rod
19 is raised thereby holding the lid
7 clear of the upper surface of the bin.
[0046] When it is required to close the lid
7 of the bin, the operator releases the pedal
15 of the bin which hinges upwards towards the bin. As the front of the pedal moves
upwards, the rear of the pedal is hinged downwards thereby lowering the actuating
rod
19 to allow the lid to be lowered towards the top of the bin and so causing a rapid
compression of the air in the bellows. This in turn causes the cylindrical spigot
29 to be forced against its seat and so compressing the rubber insert and preventing
escape of air in the chamber via the aperture 28.
[0047] This prevents the lid from slamming back into position, as the actuating rod
19 is lowered. During this time the actuating member
36 is lowered through the slot
22 in the shroud
21 thereby so that the bellows
34 are compressed within the shroud. However, once and equilibrium has been reached
in the bellows 34, the second stage of the lowering then begins with the compressed
air in the bellows 34 slowly escaping through the aperture 28 controlling the decent
of the lid through the final quarter of it's movement.
[0048] As the air in the bellows
34 is forced through the aperture
28 in the cap, the actuating rod
19 is slowly returned from the raised to the lowered position thereby gently lowering
the lid
7 of the bin onto the top edge of the bin.
[0049] The weight of the lid
7 of the bin retains the bellows
34 in the compressed condition shown in Figure.
[0050] It should also be noted that for any particular arrangement the volume of air within
the bellows 34 is determined by the mass of lid which has to have it's movement controlled.
The cylindrical spigot 29 is weighted to prevent leakage of air under rapid compression
but to allow controlled release under other conditions. The weight of the spigot compresses
the rubber insert, but not overly thereby enabling the controlled release. Further
when the bellows 34 are extended the spigot 29 is not too heavy to stay seated but
moves to allow air through aperture 28 into the bellows 34, but is heavy enough to
remain located in the boss.
1. A shock absorber adapted for use on a pedal bin in which the lid of the pedal bin
is opened and closed by an actuating member, the shock absorber comprising damping
means connected to the actuating means to limit the speed of movement of the actuating
means when the lid of the bin is opened or closed.
2. A shock absorber according to claim 1, wherein the shock absorber comprises a body
which is adapted to be mounted on the bin adjacent to the actuating means of the bin,
the damping means being mounted within the body.
3. A shock absorber according to claim 2, wherein the damping means comprises bellows
mounted which may expand or retract within the body.
4. A shock absorber according to claim 3, wherein means are provided to connect the bellows
to the actuating member of the bin.
5. A shock absorber according to claim 4, wherein the connecting means comprises a planar
member, one end of which is provided with a recess to receive the actuating member
and the other end of which is connected to the leading end of the bellows.
6. A shock absorber according to claim 5, wherein the recess is defined between two arms
of the planar member and means are provided to alter the distance between the two
arms thereby altering the size of the recess to allow the connecting means to be securely
affixed to the actuating means of the bin.
7. A shock absorber according to claim 5 or 6, wherein the body of the shock absorber
is provided with a longitudinal slot along at least part of the length thereof, through
which the planar member extends as the bellows are expanded and retracted within the
body.
8. A shock absorber according to any one of claims 5 to 7, wherein the body is provided
with an end cap closing the end of the body remote from the planar member.
9. A shock absorber according to claim 8, wherein the end cap comprises an integrally
formed hollow boss which extends into the body and is received within the free end
of the bellows.
10. A shock absorber according to claim 9, wherein an aperture is formed in the outer
surface of the end cap allowing air to be drawn into the hollow boss.
11. A shock absorber according to claim 10, wherein a weight is provided within the boss,
the weight being moveable between a position wherein the aperture in the end cap is
closed by the weight and a position where the weight is lifted free of the aperture
to allow air to be drawn into the boss.
12. A shock absorber according to claim 11, wherein a limit stop is mounted on the boss
to limit the movement of the weight between the two extreme positions.
13. A shock absorber according to any one of claims 2 to 12, wherein the body is formed
of a rigid plastics material.
14. A shock absorber according to any one of claims 3 to 13, wherein the bellows are formed
of a resilient plastics material.