Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to telescopic handles. More
particularly, tlle invention pro~ides a simple and practical telescopic
tool handle which is operable at an infinite number of lengths.
Extensible tool handles are advantageous because although
longer handles are usually preferred because of the increased leverage
provided, due to space limitations it is often only possible to use a
tool with a relatively short handle.
In the prior art~ extensible tool handles are known which
require the addition or removal of various pieces. Such tool handles
have a number of disadvantages; in particular, the addition and removal
of the various pieces is often time consuming and various pieces can
easily be misplaced or lost. Further, these tool handles are only
sable at a limited number of specific lengths. l`elescopic tool handles
are known in the prior art; however, none of the known handles combine
the advantages of the present invention of being simple in construction
and at the same time providing a handle which may be securely used in an
infinite number of positions.
According to the present invention there is provided a handle
comprising inner and outer telescoping members. The members are relatively
movable between a contracted position in which there is a substantial
overlap of the members and a fully extended position in which one member
ex~ends a substantial distance beyond the other member. A detent is
carried on one member. Spring means urge the detent into engagement
with a longitud mally extendi.ng surface of the other member. A recess
is formed in the other member at a position such that in the fully
extended position the detent is pressed into engagement with the recess.
The detent and the recess are configured so that extension of the members
beyond the fully extended position is prevented but contraction of the
members from the fully extended position is permitted. One of the inner and
outer members have a portion which, between the two positions~ fits closely with
the other of the inner and outer members whereby relative extension or contrac-
tion is frictionally resisted. Between the two positions, the detent is urged
into sliding contact with ~he longitudinally extending surface so that extension
or contraction of the members is further frictionally resisted.
These handles are advantageous in that they are simply and easily
moved between the fully contracted and the Eully extended positions and in that
the frictional resistance resulting from the close fit of the inner and outer
members and from the detent as it moves against the longitudinally extending
surface helps to secure the handle in any desired position. ~urther, because
the outer member cannot be easily removed from the inner member, one avoids the
possibility of any components being lost or misplaced.
In a preferred embodimentg the detent has a first lateral surface
perpendicular to the longitudinally extending surface and the recess has a first
lateral surface tapered with respect to and a second lateral surface perpen-
dicular to the longitudinally extending surlace. The second lateral surface of
the recess engages with the first lateral surface of the detent to prevent
extension of the outer member beyond the fully extended position. Upon con-
traction of the members from the fully extended position, the first lateral
surface of the recess cams the de~ent out of the recess thereby permitting
further contraction of the members.
In another preferred embodiment, the inner member has an
exterior surface which is circular in cross-section, the outer member
has an interior surface which is circular in cross-section and the
recess extends around the entire circumference of the interior surface.
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The inner and outer members are then able to rotate indefinitely with
respect to each other.
In a further preferred embodiment, one end of the outer member
is closed so that when the ilmer member moves into and out of the outer
member it acts like a piston in a cylinder, forcing air out of or into
the outer member, as the case may be. In this embodiment, the clearance
between the exterior surface of the inner member and the interior surface
of the outer member is made sufficiently close so that air movement is
restricted and relative movement of the members is therefore pneumatically
resisted.
In drawings which are illustrative of a preferred embodiment
of the invention,
Figure 1 is a view, partially in section, of a tool incorpora-
ting a fully contracted handle according to the present invention,
Figure 2 is a view, partially in section, of a tool incorpora-
ting a fully extended handle according to the present invention,
Figure 3 is a cross-sectional view of the tool handle taken
along line III-III of Figure 2,
Figure 4 is a view, partially in section, bf a tool incorpora-
ting an alternative embodiment of the handle according to the present
invention~
Figure 5 is a partial sectional view of an alternative embodiment
of the handle according to the present invention.
Referring to Figure 1, there is shown a tool consisting of a
drive rachet head 1 of a type which is well known in the art, and a
handle 3 consisting of an inner member 5 and an outer member 7.
The inner member S consists of a circular shaft 6~ the end
portion 9 of which has a slightly greater diameter than the rest o the
. , .
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shaft. ~ousing 11 in end portion 9 holds a detent 13 and a spring 15
which urges the detent 13 outwardly of ~he housing 11.
Outer member 7 has an ex~erior surface 8 which serves as a
gripping means for the handle. Outer member 7 has a circular interior
opening 17 which is only slightly larger than the diameter of the end
portion 9 of ~he inner member 5.
A recess 19 is formed in the longitudinally extending interior
surace 21 of the outer member 7. The recess extends around the entire
inner circumference of the outer member 7. The recess 19 is sized to
rec0ive the top portion of detent 13. The recess 19 ha.s a first lateral
surface 25 which is tapered relative to the longitudinally extending
interi.or surface 21 of outer member 7. The recess 19 has a second
latera]. surface 27 which is perpendicular to the longitudinally extending
interior surface 21.
The detent 13 has a first lateral surface 28 which is perpendicular
to shat 6 and a top surface 2~ which is arranged to be parallel to the
longitudinally extendi.ng interior surface 21.
The outer member 7 may be extended relative to inner member 5
until the fully extended position shown in Figure 2 is reached. Because o~
the close fit of outer member 7 over end portion 9 of inner member 5, the
surface irregularities of their mating sur~aces are brought together
whenever the user of the tool places a force upon the handle 3. This causes
frictional resistance to relative rotation and relative extension or
contraction of the members which increases as the user increases the force
p].aced upon the handle. During extension or contraction of the members,
detent 13 is urged by spring 15 against the longitudinally extending
i.nterior surface 21 and accordingly relative movement between the inner
member 5 and the outer member 7 is further frictionally resisted.
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This additional frictional resistance caused by the detent is of greatest
significance when relatively small forces are applied to the handle and
the frictional resistance caused by the bringing together of the surface
irregularities of outer member 7 and end portion 9 are accordingly relatively
small. When the fully extended position is reached the spring 15 urges
the detent 13 into recess 19. Because the second lateral surface 27 of
recess 19 is perpendicular to the longitudinally extending interior
surface 21 and the first lateral surface 28 of the detent 13 is perpendicular
to the shaft 6, they engage so as to preven* extension beyond ~he fully
extended position. Because the first lateral surface 25 of recess l9 is
tapered, upon urging of the members together from the fully extended
position, the tapered first lateral surface 25 of the recess 19 will cam
the detent 13 out of the recess l9 and into the housing ll thereby
permitting the members to be contracted. [t will be seen that although
the tapered first lateral surface 25 of the recess 19 permits the members
to be contracted from the fully extended position, there is an initial
resistance to contraction. Accordingly, this reduces the possibility
when one is using the tool in the fully extended position that the
handle will suddenly and unexpectedly contract from the fully extended
position. It is advantageous that the tool be particularly secure
against sudden contraction or extension while in the fully extended
position because this is the position which would be used when one
requires the greatest torque and is therefore exerting the greatest
force upon the handleO ~s indicated above, when not in the fully extended
posi*ion, the frictional resistance between the outer member 7 and end
portion 9 and between the detent 13 and the longitudinally extending
interior surface 21 helps to avoid sudden or unexpected extension or
contraction of the handle while it is being used.
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Because the outer end 29 of the outer member 7 is closed and
because of the close fit of the outer member 7 over the inner member 5,
there is little room provided for movement of air. Accordingly~ there
is a pneumatic resistance to the extension or contraction of the handle.
For example, as one moves from the fully extended position shown in
Pigure 2 ~o the fully contracted position shown in Figure 1 the air
shown at 31, being able to only slowly move past the end portion 9 of
the inner member 5, compresses and resists further contraction of the
handle. This provides an additional resistance to any sudden or unexpected
extension or contraction of the handle when it is being used.
An alternative embodiment of a tool according to the present
invention is shown in Figure 4. This tool consists of a drive ratchet
head 1' and a handle 3' consisting of an inner member 5' and an outer
member 7'. In this embodiment the inner member 5' does not have an
enlarged end portion 9 (See Figure 1). Instead outer member 7' is provided
with portions 9' of a reduced diameter on:Ly slightly larger than the outer
diameter of inner member 5'. Because of the close fit of portions 9' over
inner member 5', the surface irregularities are brought toge~her whenever
the user of the tool places a force upon handle 3'. This causes frictional
resistance to relative rotation and relative extension or contraction of the
members. In this embodiment the force on the outer member 7' is more likely
to be applied by the user remote from the contact area between the inner
member 5' and the outer member 7' because the portions 9' are at the ~eading
edge of outer member 7'. This is advantageous because it increases the
frictional resistance caused by the bringing together of the surface
irregularities of inner member 5' and portions 9'O
Pigure S shows a part of a tool as shown in Pigure 1 with the
exception that at one point around the circumference of recess 19 an
- 6 -
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opening 33 is provided for receiving the top of detent 13. The detent 13 is
prevented -from falling out of the handle 3 by projections 35. When the
detent 13 is received in opening 33, relative rotation of the inner member
5 and the outer member 7 is prevented. In order to allow relative rotation
again, one simply presses the detent 13 inwardly while at the same time
rotating the outer member 7 relative to inner member 5.
, . . .
