U.S. patent application number 15/344301 was filed with the patent office on 2017-05-11 for telescopic wand for a vacuum cleaner.
This patent application is currently assigned to Dyson Technology Limited. The applicant listed for this patent is Dyson Technology Limited. Invention is credited to Adam David LAMBERT, Paul Andrew MCLUCKIE.
Application Number | 20170127898 15/344301 |
Document ID | / |
Family ID | 55132434 |
Filed Date | 2017-05-11 |
United States Patent
Application |
20170127898 |
Kind Code |
A1 |
LAMBERT; Adam David ; et
al. |
May 11, 2017 |
Telescopic Wand for a Vacuum Cleaner
Abstract
A telescopic wand for a vacuum cleaner includes an inner tube,
an outer tube, and a catch, wherein the inner tube includes
multiple projections, the outer tube includes a pair of bosses, and
the catch includes a locking stub. The catch pivotally attaches to
the outer tube and pivots between lock and unlock positions. The
locking stub projects between two of the projections in the lock
position and is lifted clear of the projections in the unlock
position. Applying a push or pull force to the wand when in the
locked position causes a first projection to abut a side of the
locking stub and the bosses to abut an opposite side thereof, and
applying the push or pull force to the wand when in the unlock
position causes the inner tube to slide relative to the outer tube
and the second projection to pass between the bosses.
Inventors: |
LAMBERT; Adam David;
(Swindon, GB) ; MCLUCKIE; Paul Andrew; (Bristol,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Dyson Technology Limited |
Wiltshire |
|
GB |
|
|
Assignee: |
Dyson Technology Limited
Wiltshire
GB
|
Family ID: |
55132434 |
Appl. No.: |
15/344301 |
Filed: |
November 4, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A47L 9/244 20130101 |
International
Class: |
A47L 9/24 20060101
A47L009/24 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 6, 2015 |
GB |
1519658.7 |
Claims
1. A telescopic wand for a vacuum cleaner, the wand comprising an
inner tube, an outer tube, and a catch, wherein: the inner tube
comprises a plurality of projections, the outer tube comprises a
pair of bosses, and the catch comprises a locking stub; the catch
is pivotally attached to the outer tube and pivots between a lock
position and an unlock position; the locking stub projects into a
recess between two of the projections when the catch is in the lock
position, and the locking stub is lifted clear of the projections
when the catch is in the unlock position; applying a push or pull
force to the wand when the catch is in the lock position causes a
first of the two projections to abut a side of the locking stub and
the bosses to abut an opposite side of the locking stub; and
applying the push or pull force to the wand when the catch is in
the unlock position causes the inner tube to slide relative to the
outer tube and a second of the two projections to pass between the
bosses.
2. The telescopic wand of claim 1, wherein the inner tube comprises
a flat section from which the projections project, and the flat
section is wider than the projections such that the flat section
extends along either side of each projection.
3. The telescopic wand of claim 2, wherein the inner tube has a
cross-sectional shape corresponding to a major segment of a circle
or oval, and the flat surface corresponds to a chord of the major
segment.
4. The telescopic wand of claim 1, wherein the outer tube has a
cross-sectional shape that is circular or oval.
5. The telescopic wand of claim 1, wherein the catch pivots about a
pivot point that is located above the projections.
6. The telescopic wand of claim 1, wherein the outer tube comprises
a pair of further bosses, applying a push force to the wand when
the catch is in the lock position causes the first of the two
projections to abut the side of the locking stub and the bosses to
abut the opposite side of the locking stub, and applying a pull
force to the wand when the catch is in the lock position causes the
second of the two projections to abut the opposite side of the
locking stub and the further bosses to abut the side of the locking
stub.
7. The telescopic wand of claim 6, wherein applying the push or
pull force to the wand when the catch is in the unlock position
causes the inner tube to slide relative to the outer tube and the
first of the two projections to pass between the further
bosses.
8. The telescopic wand of claim 1, wherein applying the push or
pull force to the wand when the catch is in the lock position
causes the first of the projections to apply a first force to the
locking stub and the bosses to apply a second force to the locking
stub, and the second force is equal and opposite to the first force
and has the same line of action as the first force.
9. A telescopic wand for a vacuum cleaner, the wand comprising an
inner tube, an outer tube, and a catch, wherein: the inner tube
comprises a plurality of projections, the outer tube comprises a
pair of bosses, and the catch comprises a locking stub; the catch
is pivotally attached to the outer tube and pivots between a lock
position and an unlock position; the locking stub projects into a
recess between two of the projections when the catch is in the lock
position, and the locking stub is lifted clear of the projections
when the catch is in the unlock position; and applying a push or
pull force to the wand when the catch is in the lock position
causes a first of the two projections to apply a first force to the
locking stub and the bosses to apply a second force to the locking
stub, the second force being equal and opposite to the first force
and having the same line of action as the first force.
10. The telescopic wand of claim 9, wherein applying the push or
pull force to the wand when the catch is in the unlock position
causes the inner tube to slide relative to the outer tube and a
second of the two projections to pass between the bosses.
11. The telescopic wand of claim 9, wherein the outer tube
comprises a pair of further bosses, applying a push force to the
wand when the catch is in the lock position causes the first of the
two projections to apply the first force to the locking stub, and
applying a pull force to the wand when the catch is in the lock
position causes a second of the two projections to apply a third
force to the locking stub and the further bosses to apply a fourth
force to the locking stub, and the fourth force is equal and
opposite to the third force and has the same line of action as the
third force.
12. The telescopic wand of claim 11, wherein applying the push or
pull force to the wand when the catch is in the unlock position
causes the inner tube to slide relative to the outer tube and the
first of the two projections to pass between the further bosses.
Description
REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to United Kingdom
Application No. 1519658.7, filed Nov. 6, 2015, the entire contents
of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a telescopic wand for a
vacuum cleaner.
BACKGROUND OF THE INVENTION
[0003] The telescopic wand of a vacuum cleaner may comprise an
inner tube, an outer tube, and a catch for locking the position of
the inner tube relative to the outer tube. The catch may be
pivotally attached to the outer tube for movement between a lock
position and an unlock position. When the catch is in the lock
position, push and pull forces applied to the wand must be borne by
the pivot. However, the applied force can be significant and thus
the required pivot may compromise the size and/or the assembly of
the wand. Additionally, depending on the location of the pivot, the
catch may pivot downwards or upwards in response to the applied
force. With sufficient applied force, the catch may jam in the lock
position or pivot to the unlock position.
SUMMARY OF THE INVENTION
[0004] The present invention provides a telescopic wand for a
vacuum cleaner, the wand comprising an inner tube, an outer tube,
and a catch, wherein: the inner tube comprises a plurality of
projections, the outer tube comprises a pair of bosses, and the
catch comprises a locking stub; the catch is pivotally attached to
the outer tube and pivots between a lock position and an unlock
position; the locking stub projects into a recess between two of
the projections when the catch is in the lock position, and the
locking stub is lifted clear of the projections when the catch is
in the unlock position; applying a push or pull force to the wand
when the catch is in the lock position causes a first of the two
projections to abut a side of the locking stub and the bosses to
abut an opposite side of the locking stub; and applying the push or
pull force to the wand when the catch is in the unlock position
causes the inner tube to slide relative to the outer tube and a
second of the two projections to pass between the bosses.
[0005] Consequently, when the catch is in the lock position and a
push or pull force is applied to the wand, the force of the first
projection on the catch is opposed by the bosses. The pivot between
the catch and the outer tube is not therefore required to bear the
full magnitude of the applied force. As a result, a smaller pivot
may be employed that would otherwise yield if subjected to the full
magnitude of the applied force.
[0006] When the catch is in the unlock position and the push or
pull force is applied to the wand, the inner tube slides relative
to the outer tube and the second of the two projections passes
between the bosses. By having an arrangement in which the second
projection passes between the bosses, it is possible to locate the
bosses at a similar height to that of the first projection. This
then has the benefit that, when the catch is in the lock position
and a push or pull force is applied to the wand, the force applied
by the bosses to the catch may have a similar line of action to
that applied by the first projection. As a result, the catch
experiences less torque and is therefore less likely to pivot when
the push or pull force is applied.
[0007] The inner tube may comprise a flat section from which the
projections project, and the flat section may be wider than the
projections such that the flat section extends along either side of
each projection. This then has the benefit that the bosses of the
outer tube may be located at the same or a similar height as the
projections in a relatively compact manner In particular, the outer
tube may have an inner diameter that is only slightly larger than
the outer diameter of the inner tube so as to permit sliding
movement. The flat surface of the inner tube then provides the
space for the bosses of the outer tube.
[0008] The inner tube may have a cross-sectional shape
corresponding to a major segment of a circle or oval, and the flat
surface may correspond to the chord of the major segment.
Furthermore, the outer tube may have a cross-sectional shape that
is circular or oval.
[0009] The catch may pivot about a pivot point that is located
above the projections. This then has the advantage that a
relatively compact catch may be employed. In the absence of the
bosses, a moment of force or torque may be exerted on the catch in
response to the push or pull force. This torque would then cause
the catch to pivot downwards or upwards, which may cause the catch
to jam in the lock position or move to the unlock position. By
employing an arrangement in which the second projection passes
between the bosses, the net force applied by the bosses may have a
similar line of action to that applied by the first projection. As
a result, the catch experiences less torque in response to the
applied force. It is therefore possible to locate the pivot point
above the projections without fear of the catch becoming jammed in
the lock position or moving to the unlock position.
[0010] The outer tube may comprise a pair of further bosses.
Applying a push force to the wand when the catch is in the lock
position then causes the first projection to abut the side of the
locking stub and the bosses to abut the opposite side of the
locking stub. Furthermore, applying a pull force to the wand when
the catch is in the lock position causes the second projection to
abut the opposite side of the locking stub and the further bosses
to abut the side of the locking stub. As a result, the pivot
between the catch and the outer tube is not required to bear either
a push force or a pull force.
[0011] When the catch is in the unlock position and the push or
pull force is applied to the wand, the inner tube may slide
relative to the outer tube and the first projection may pass
between the further bosses. By having an arrangement in which the
first projection passes between the further bosses, it is possible
to locate the further bosses at a similar height to that of the
second projection. This then has the benefit that, when the catch
is in the lock position and a pull force is applied to the wand,
the force applied by the further bosses to the catch may have a
similar line of action to that applied by the second projection. As
a result, the catch experiences less torque and is therefore less
likely to move inadvertently to the unlock position when the pull
force is applied.
[0012] When the catch is in the lock position and the push or pull
force is applied to the wand, the first projection may be said to
apply a first force to the locking stub and the bosses may be said
to apply a second force to the locking stub. The second force may
then be equal and opposite to the first force and have the same
line of action as the first force. As a result, the pivot is not
required to bear any of the applied force. Moreover, no torque is
exerted on the catch and thus the catch does not pivot in response
to the applied force.
[0013] The present invention also provides a telescopic wand for a
vacuum cleaner, the wand comprising an inner tube, an outer tube,
and a catch, wherein: the inner tube comprises a plurality of
projections, the outer tube comprises a pair of bosses, and the
catch comprises a locking stub; the catch is pivotally attached to
the outer tube and pivots between a lock position and an unlock
position; the locking stub projects into a recess between two of
the projections when the catch is in the lock position, and the
locking stub is lifted clear of the projections when the catch is
in the unlock position; applying a push or pull force to the wand
when the catch is in the lock position causes a first of the two
projections to apply a first force to the locking stub and the
bosses to apply a second force to the locking stub, the second
force being equal and opposite to the first force and having the
same line of action as the first force.
[0014] Since the bosses apply a force to the locking stub that is
equal and opposite to and has the same line of action as the force
applied by the first projection, the pivot between the catch and
the outer tube is not required to bear the push or pull force. It
is therefore possible to employ a pivot that would otherwise yield
if subjected to the push or pull force. Moreover, since the forces
applied by the bosses and the first projection have the same line
of action, no torque is exerted on the catch as a result of the
push or pull force and thus inadvertent pivoting of the catch may
be avoided.
[0015] The outer tube may comprise a pair of further bosses.
Applying a push force to the wand when the catch is in the lock
position then causes the first of the two projections to apply the
first force to the locking stub. Furthermore, applying a pull force
to the wand when the catch is in the lock position causes a second
of the two projections to apply a third force to the locking stub
and the further bosses to apply a fourth force to the locking stub.
The fourth force may then be equal and opposite to the third force
and have the same line of action as the third force. As a result,
the pivot between the catch and the outer tube is not required to
bear either a push force or a pull force, and no torque is exerted
on the catch as a result of the push or pull force.
[0016] In the present description, the terms `upward`, `downward`,
`above` and `below` are made with reference to the central
longitudinal axis of the tubes. Consequently, the terms `upward`
and `downward` should be understood to mean in directions away from
and towards the longitudinal axis. Furthermore, where a first
feature is described as being located `above` or `below` a second
feature, this should be understood to mean that the first feature
is located further from or closer to the longitudinal axis.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order that the present invention may be more readily
understood, an embodiment of the invention will now be described,
by way of example, with reference to the accompanying drawings, in
which:
[0018] FIG. 1 is a perspective view of a telescopic wand in
accordance with the present invention;
[0019] FIG. 2 is a partially exploded view of the telescopic
wand;
[0020] FIG. 3 is a perspective view of a section through the
telescopic wand;
[0021] FIG. 4 is the same view as FIG. 3 but with a catch of the
telescopic wand omitted in order to better illustrate certain
features of the wand;
[0022] FIG. 5 is a side view of a sectional slice through the
telescopic wand with the catch in a lock position;
[0023] FIG. 6 is the same view as FIG. 5 but with the catch in an
unlock position;
[0024] FIG. 7 is a plan view of the section illustrated in FIG. 3;
and
[0025] FIG. 8 is an enlarged view of the boxed area of FIG. 7.
DETAILED DESCRIPTION OF THE INVENTION
[0026] The telescopic wand 1 of FIGS. 1 to 8 comprises an inner
tube 2, an outer tube 3, and a catch assembly 4.
[0027] The inner tube 2 is roughly cylindrical in shape. However,
the top of the tube 2 comprises a flat section 20. As a result, the
inner tube has a cross-sectional shape that resembles the major
segment of a circle, with the chord of the segment defining the
flat section 20. The inner tube 2 comprises a plurality of
projections 21 that project upwardly from the flat section 20. The
gap between each pair of projections 21 defines a recess 22 into
which a locking stub 44 of the catch assembly 4 projects; this is
described below in more detail. A first end of the inner tube 2 is
attachable to a cleaner head or accessory (not shown), and a second
opposite end of the inner tube 2 is received within the outer tube
3. The inner tube 2 slides relative to the outer tube 3 along a
central longitudinal axis 23, and a seal 24 is provided at the
second end of the inner tube 2 so as to minimise leaks between the
inner tube 2 and the outer tube 3.
[0028] The outer tube 3 is cylindrical in shape. A first end of the
outer tube 3 surrounds the inner tube 2, and a second opposite end
is attachable to a handle or hose (not shown). An opening 31 is
formed in the top of the outer tube 3 and is located towards the
first end of the tube 3. The outer tube 3 comprises a pair of lugs
32 located on opposite sides of the opening 31, and a stop 33
located at one end of the opening 31. As explained below, the lugs
32 act as fulcrums for the catch assembly 4, whilst the stop 33
acts to limit movement of the catch assembly 4. The outer tube 3
further comprises a pair of front bosses 34 and a pair of rear
bosses 35. The front bosses 34 are located in front of the locking
stub 44 of the catch assembly 4, and the rear bosses 35 are located
behind the locking stub 44. The bosses 34,35 are located
approximately at the same height as that of the projections 21.
Furthermore, the bosses of each pair 34,35 are located on opposite
sides of the projections 21. Consequently, when the inner tube 2
slides relative to the outer tube 3, the projections 21 passes
between the front bosses 34 and between the rear bosses 35. As
explained below, when a push or pull force is applied to the wand
1, the bosses 34,35 act to oppose the force applied by the
projections 21 to the locking stub 44.
[0029] The catch assembly 4 comprises a catch 41 and a spring
42.
[0030] The catch 41 is a unitary body that comprises a button 43
and a locking stub 44. The catch 41 is pivotally mounted to the
outer tube 3 at a pivot point 45 located between the button 43 and
the locking stub 44. More particularly, the catch 41 comprises a
pair of recesses 46 located on opposite sides of the catch 41. The
lugs 32 of the outer tube 3, which are roughly triangular in shape,
are seated in the recesses 46 and act as fulcrums for the catch
41.
[0031] The spring 42 is a leaf spring that is secured at one end to
the underside of the catch 41 and at the opposite end to the inside
of the outer tube 3. The spring 42 applies a biasing force to the
catch that pulls the locking stub 44 downwards towards the inner
tube 2.
[0032] The catch 41 pivots between a lock position (FIG. 5) and an
unlock position (FIG. 6). The catch 41 is biased by the spring 42
to the lock position. When the catch 41 is in the lock position,
the locking stub 44 projects into a recess 22 between two of the
projections 21 of the inner tube 2. Movement of the inner tube 2
relative to the outer tube 3 is then prevented. In particular, when
the inner tube 2 is moved to the left or right, the locking stub 44
abuts one of the projections 21 so as to prevent any further
movement. The catch 41 is moved to the unlock position by
depressing the button 43. When the button 43 is depressed, the
catch 41 pivots about the pivot point 45 against the biasing force
of the spring 42. As a result, the locking stub 44 pivots upwards.
The locking stub 44 is then lifted clear of the recess 22 and the
projections 21. The inner tube 2 is then free to slide left and
right relative to the outer tube 3. When the button 43 is released,
the spring 42 biases the locking stub 44 downwards. Depending on
the position of the inner tube 2, the locking stub 44 is biased
down into one of the recesses 22 or onto one of the projections 21.
In the former case, the catch 41 is returned to the lock position.
In the latter case, further movement of the inner tube 2 causes the
locking stub 44 to slide on top of the projection 21 until such
time as the locking stub 44 aligns with and snaps into one of the
recesses 22, at which point the catch 41 is returned to the lock
position.
[0033] As can be seen in FIGS. 5 and 6, the stop 33 of the outer
tube 3 limits both the upward and downward movement of the catch
41. When the button 43 is depressed and the locking stub 44 pivots
upwards, the locking stub 44 abuts the underside of the stop 33
when the locking stub 44 is clear of the projections 21. Further
downward travel of the button 43 is therefore prevented and thus
the user is provided with an indication that the catch 41 is in the
unlock position. When the button 43 is released and the spring 42
biases the locking stub 44 downwards, the catch 41 abuts the top of
the stop 33 when the catch 41 is level with the outer tube 3.
Consequently, although the locking stub 44 projects into the recess
22 when the catch 41 is in the lock position, there is nevertheless
a small clearance between the bottom of the locking stub 44 and the
top of the inner tube 2. By stopping the catch 41 at a position
level with the outer tube 3, the catch 41 is flush with the outer
tube 3 when in the lock position. This then has the advantage that
the catch 41 does not inadvertently snag on items, such as
upholstery or curtains, during use.
[0034] A more detailed description will now be provided of the
interactions that occur between the catch 41, the inner tube 2 and
the outer tube 3 when the catch 41 is in the lock position and a
push or pull force is applied to the wand 1. A push or pull force
is one that encourages the inner tube 2 to move relative to the
outer tube 3 along the longitudinal axis 23. A push force then acts
in a direction that encourages the inner tube 2 to move towards the
outer tube 3, whilst a pull force acts in a direction that
encourages the inner tube 2 to move away from the outer tube 3. So
when the catch 41 is in the unlock position and a push force is
applied to the wand 1, the inner tube 2 and the outer tube 3 are
brought together and the length of the wand 1 contracts.
Conversely, when the catch 41 is in the unlock position and a pull
force is applied to the wand 1, the inner tube 2 and the outer tube
3 separate and the length of the wand 1 expands.
[0035] FIGS. 7 and 8 illustrate the wand 1 with the catch 41 in the
lock position. The locking stub 44 projects into a recess 22
between a first projection 21a and a second projection 21b of the
inner tube 2.
[0036] When a push force is applied to the wand 1, the inner tube 2
moves relative to the outer tube 3 and the catch 41 in a direction
towards the right. The first projection 21a then abuts a first side
47 of the locking stub 44 and applies a first force to the locking
stub 44. There is a degree of play in the pivot between the catch
41 and the outer tube 3; that is to say that the catch 41 is free
to move relative to the outer tube 3 to the left and right by a
small amount before the lugs 32 of the outer tube 3 engage with the
walls of the recesses 46 in the catch 41 (see FIG. 7).
Consequently, in response to the first force, the catch 41 moves
relative to the outer tube 3 in a direction towards the right. The
rear bosses 35 then abut a second opposite side 48 of the locking
stub 44 and apply a second force to the locking stub 44. The second
force is equal and opposite to the first force and has the same
line of action as the first force. As a result, further movement of
the inner tube 2 to the right is prevented.
[0037] When a pull force is applied to the wand 1, the inner tube 2
moves relative to the outer tube 3 and the catch 41 in a direction
towards the left. The second projection 21b then abuts the second
side 48 of the locking stub 44 and applies a third force to the
locking stub 44. Owing to the degree of play in the pivot between
the catch 41 and the outer tube 3, the third force causes the catch
41 to move relative to the outer tube 3 in a direction towards the
left. The front bosses 34 then abut the first side 47 of the
locking stub 44 and apply a fourth force to the locking stub 44.
The fourth force is equal and opposite to the third force, and has
the same line of action as the third force. As a result, further
movement of the inner tube 2 to the left is prevented.
[0038] Irrespective of whether a push force or a pull force is
applied to the wand 1, the bosses 34,35 apply a force to the
locking stub 44 that is equal and opposite to and has the same line
of action as the force applied by the projection 21 of the inner
tube 2. As a result, the pivot between the catch 41 and the outer
tube 3 is not required to bear the push or pull force. It is
therefore possible to employ a pivot that would otherwise yield if
subjected to the push force or pull force.
[0039] The bosses 34,35 apply a force having the same line of
action as that applied by the projection 21. This is made possible
by locating the bosses 34,35 on opposite sides of the projection 21
at approximately the same height as the projection 21. As a
consequence of locating the bosses 34,35 in this manner, the
projections 21 pass between the bosses 34,35 when the catch 41 is
in the unlock position and a push or pull force is applied to the
wand 1.
[0040] The catch 41 pivots relative to the outer tube 3 at a point
45 that is located above the projections 21. Consequently, if the
bosses 34,35 were omitted and the pivot were designed to withstand
the applied force, the force applied to the catch 41 by the outer
tube 3 would have a different line of action to that applied to the
catch 41 by the projections 21. In particular, the force applied by
the outer tube 3 would have a higher line of action. As a result, a
moment of force or torque would be exerted on the catch 41. This
torque would cause the locking stub 44 to pivot downwards or
upwards depending on whether the applied force is a push force or a
pull force. The stop 33 of the outer tube 3 would prevent the
locking stub 44 from pivoting downwards. However, the locking stub
44 may pivot upwards against the biasing force of the spring 42. If
the force applied to the wand 1 were sufficiently strong, the catch
41 could move to the unlock position. By providing the bosses
34,35, no torque is exerted on the catch 41. As a result, the pivot
point 45 of the catch 41 may be located above the projections 21
without fear of the catch 41 moving inadvertently to the unlock
position.
[0041] Owing to dimensional and geometric tolerances in the wand 1,
the forces applied to the catch 41 by the projections 21 and the
bosses 34,35 may not have exactly the same line of action.
Accordingly, when a push or pull force is applied to the wand 1, a
torque may be exerted on the catch 41. However, any torque will be
relatively small. Accordingly, even if the applied force is
relatively strong, the resulting torque will be insufficient to
move the catch 41 to the unlock position.
[0042] The inner tube 3 has a flat section 20 from which the
projections 21 project. The flat section 20 is then wider than the
projections 21 such that the flat section 20 extends along either
side of each projection 21. This then has the benefit that the
bosses 34,35 of the outer tube 3 can be located at approximately
the same height as the projections 21 in a relatively compact
manner In particular, the outer tube 3 may have an inner diameter
that is only slightly larger than the outer diameter of the inner
tube 2 so as to permit sliding movement. The flat section 20 on the
top of the inner tube 2 then provides the space for the bosses
34,35 of the outer tube 3.
[0043] Whilst the outer tube 3 has both front bosses 34 and rear
bosses 35, significant benefits may be achieved by having only
front bosses 34 or only rear bosses 35. For example, when the wand
1 is used to manoeuvre a cleaner head over a surface, the push
force applied to the wand 1 is generally greater than the pull
force. The provision of rear bosses 35 would therefore enable a
pivot to be employed that is capable of bearing the smaller pull
force but would yield if subjected to the larger push force. As a
further example, the pivot may be designed to bear both the push
force and the pull force. The front bosses 34 may then be provided
in order to prevent the catch 41 from moving inadvertently to the
unlock position when a relatively strong pull force is applied to
the wand 1.
[0044] The inner tube 3 has a plurality of recesses 22 into which
the locking stub 44 of the catch 41 can project. This then has the
benefit that the length of the wand 1 can be adjusted according to
the height of the user or the intended use. Conceivably, however,
the inner tube 3 may comprise a single recess 22 located between a
single pair of projections 21. The locking stub 44 would then
project into the recess 22 when the wand 1 is fully extended. Only
one of the pair of projections 21 would then pass between both the
front bosses 34 and the rear bosses 35 when the inner tube 2 slides
relative to the outer tube 3; the other of the pair of projections
21 would pass between only the rear bosses 35.
* * * * *