Locking mechanism for telescopically adjustable extension pole

A locking mechanism for a telescopically adjustable extension pole is disclosed. The locking mechanism includes a collar member and a locking trigger mechanism preferably comprising a bottom trigger member and a top trigger member having a locking pin therein. The top trigger member grippingly engages the collar member which is attached to the outer sleeve of the pole. By depressing the bottom trigger member, the top trigger member moves laterally outwardly retracting the locking pin from an aperture in the inner sleeve permitting the length of the extension pole to be telescopically adjusted. By releasing the bottom trigger member, the top trigger member moves laterally inwardly causing the locking pin to be received within an aperture in the inner sleeve so as to interlock the inner sleeve within the outer sleeve at the approximate desired length of the extension pole.

TECHNICAL FIELD
 The present invention relates, in general, to an adjustable extension pole
 and, more particularly, to an improved locking mechanism for a
 telescopically adjustable extension pole.
 BACKGROUND ART
 There are numerous types of extension poles that can be used for painting
 or other applications, e.g., sweeping attachments, swimming pool cleaning
 nets, and which allow the user to adjust the overall length thereof. For
 example, such poles permit the attachment of a paint roller frame to the
 end thereof allowing the painter to paint walls and ceilings without the
 use of a ladder. Such poles typically utilize telescoping members for
 length adjustment purposes and some type of locking mechanism to interlock
 the telescoping members after the desired length of the pole has been
 attained. It has been found that these locking mechanisms usually have
 some type of inherent structural or operational disadvantages. For
 example, the adjustable extension pole disclosed in U.S. Pat. No.
 5,220,707 (Newman, Sr., et al.) utilizes a locking mechanism comprising a
 Belleville-type washer arrangement which is connected to a pin which
 interlocks the outer telescoping sleeve within the inner telescoping
 sleeve. By depressing a push button operatively connected to the
 Belleville-type washer, the washer is deformed causing the pin to be
 withdrawn from the inner sleeve permitting the inner sleeve to be
 telescopically adjusted within the outer sleeve. Operationally, the
 aforementioned locking mechanism has some inherent disadvantages since,
 through use, the washer becomes fatigued causing the locking mechanism to
 malfunction. In addition, since a push button arrangement is used, paint
 can be easily entrapped under and around same affecting the "snap-action"
 ability of the Belleville-type washer.
 Another tube or sleeve locking mechanism is disclosed in U.S. Pat. No.
 3,596,946 (Burton, et al.) which utilizes an unidirectional cam lock
 arrangement to interlock the sleeves after the desired length of the
 extension pole has been attained. In this case, the inner and outer
 sleeves must be properly aligned in order to operate the cam locking
 arrangement and the cam locking arrangement is susceptible to paint
 becoming entrapped therein causing the malfunction of same. Another tube
 or sleeve locking mechanism is disclosed in U.S. Pat. No. 4,662,771 (Roe,
 et al.). In this case, the locking mechanism is comprised of a relatively
 complex ball and detent arrangement received between machined sleeves
 connected to the extension pole. The ball and detent arrangement is
 relatively costly to produce, and the resulting locking mechanism is
 susceptible to paint being entrapped therein resulting in the possible
 malfunction of same. A further tube or sleeve locking mechanism is
 disclosed in U.S. Pat. No. 3,603,623 (Widman). This locking mechanism
 utilizes oppositely wound coil springs which surround the inner tubular
 sleeve. By changing the bias on the springs which can be accomplished by
 moving external knobs on the outer surface of the locking mechanism, the
 inner sleeve is released permitting its telescopic adjustment within the
 outer sleeve. In this case, the coil springs are subject to fatigue and
 breakage, and the locking mechanism is susceptible to paint being
 entrapped therein due to its use of external knobs to change the bias on
 the springs within same. Lastly, U.S. Pat. No. 5,288,161 (Graves, et al.)
 discloses a locking mechanism which interlocks the end of an extension
 pole to the end of a paint roller frame. In this case, the extension pole
 is not telescopically adjustable, however, the locking mechanism permits
 the attachment of the pole, which can be any length, to the end of the
 paint roller frame. The locking mechanism disclosed in this patent is
 comprised of a lever arrangement which is external to the end of the pole,
 and thus, is very susceptible to paint being entrapped therein causing the
 locking mechanism to become difficult to operate or inoperable.
 Because of the foregoing inherent disadvantages associated with presently
 available extension poles, it has become desirable to develop an extension
 pole locking mechanism that is durable, is easy to produce, assemble and
 operate and which is not susceptible to paint being entrapped therein.
 SUMMARY OF THE INVENTION
 The present invention solves the problems associated with prior art
 extension poles and other problems by providing an extension pole locking
 mechanism which comprises a minimum number of components, is less
 susceptible to paint being entrapped therein, and is extremely simple to
 produce and operate. The locking mechanism of the present invention
 comprises an outer tubular sleeve, an inner tubular sleeve received within
 the outer tubular sleeve and a collar assembly attached to the outer
 tubular sleeve. The collar assembly comprises a collar member attached to
 the outer tubular sleeve and a locking trigger mechanism which is received
 over the collar member and includes a bottom trigger member and a top
 trigger member having a locking pin therein. The top trigger member has a
 circular configuration and grippingly engages the collar member. The
 bottom trigger member has a U-shaped configuration and interlocks with the
 top trigger member. Because of the U-shaped configuration of the bottom
 trigger member, when the top and bottom trigger members are interlocked, a
 gap is created between the inner surface of the bottom trigger member and
 the collar member. By depressing the bottom trigger member, the gap
 between the bottom trigger member and the collar member closes causing the
 top trigger member to move laterally outwardly retracting the locking pin
 from the inner tubular sleeve permitting the length of the extension pole
 to be adjusted. After the desired length of the pole has been attained, if
 pressure is released on the bottom trigger member, the top trigger member
 will move laterally inwardly causing the locking pin therein to be
 received in an aperture in the inner tubular sleeve locking the inner
 tubular sleeve within the outer tubular sleeve at the approximate desired
 length of the extension pole.
 Accordingly, it is an object of the present invention to provide an
 extension pole locking mechanism which utilizes a minimum number of
 components.
 Another object of the present invention is to provide an extension pole
 locking mechanism which is less susceptible to paint being entrapped
 therein.
 A still another object of the present invention is to provide an extension
 pole locking mechanism that is durable.
 A further object of the present invention is to provide an extension pole
 locking mechanism that is relatively inexpensive to produce and is easy to
 assemble.
 A still further object of the present invention is to provide an extension
 pole locking mechanism that can be easily replaced, if necessary.

DESCRIPTION OF THE PREFERRED EMBODIMENT
 Referring now to the drawings where the illustrations are for the purpose
 of describing the preferred embodiment of the present invention and not
 intended to limit the invention described herein, FIG. 1 is an exploded
 perspective view of a telescopically adjustable extension pole 10
 utilizing the sleeve locking mechanism of the present invention. Extension
 pole 10 is comprised of an outer tubular sleeve 12 having a grip 14 at one
 end thereof and a collar assembly 16 at the opposite end thereof, and an
 inner tubular sleeve 18 received within the outer tubular sleeve 12. The
 inner tubular sleeve 18 has an end cap 20 attached to one end thereof and
 a threaded connector 22 attached to the opposite end thereof.
 The outer tubular sleeve 12 can be fabricated from a metallic or a
 non-metallic material, such as nylon or the like. If a nylon material is
 utilized, fiberglass can be added to same to increase strength. The grip
 14 has an inner diameter slightly less than the outer diameter of outer
 tubular sleeve 12 permitting grip 14 to be slip fit over end 30 of outer
 tubular sleeve 12 and to be grippingly retained thereon. The opposite end
 32 of outer tubular sleeve 12 is press fit into one end 34 of collar
 assembly 16. The inner tubular sleeve 18 is sized so as to be receivable
 and telescopically movable within outer tubular sleeve 12 and is typically
 formed from metallic material and is preferably hexagonal in
 cross-section, however, the configuration of this sleeve 18 can be
 polysided, such as square or octagonal. A plurality of apertures 36 is
 provided in a spaced-apart relationship along one surface of the inner
 tubular sleeve 18. End cap 20 has a configuration complementary to inner
 tubular sleeve 18 permitting it to be received within end 38 of inner
 tubular sleeve 18 and to be retained therein by a fastener 40 which passes
 through the inner tubular sleeve 18 and into end cap 20. End cap 20 has a
 circular flanged surface 42 at one end thereof. Flanged surface 42 has an
 outer diameter slightly less than the inner diameter of the outer tubular
 sleeve 12. Threaded connector 22 is received within the opposite end 44 of
 inner tubular sleeve 18 and is retained therein by oppositely disposed
 fasteners 46 which are threadably received through the inner tubular
 sleeve 18 and into the body of threaded connector 22. Threaded connector
 22 has a threaded end 48 which is received in a complementary female
 threaded connector provided in the end of the handle for a paint roller
 frame (not shown).
 Collar assembly 16 is comprised of a collar member 50, a bottom trigger
 member 52, a top trigger member 54 and a locking pin 56 (shown in FIG. 2).
 Referring now to FIG. 2, which is cross-sectional view of the collar
 member 50 and illustrates its attachment to the outer tubular sleeve 12
 and the position of the inner tubular sleeve 18 within same, collar member
 50 is generally circular in cross-section and is comprised of an end
 portion 58, a first bore portion 60 and a second bore portion 62. End
 portion 58 has a bore 64 therethrough having a configuration complementary
 to the configuration of the inner tubular sleeve 18, i.e., if inner
 tubular sleeve 18 is hexagonal in shape, bore 64 in end portion 58 will be
 similarly hexagonal in shape and will be sized slightly larger than inner
 tubular sleeve 18 permitting inner tubular sleeve 18 to be telescopically
 movable within outer tubular sleeve 12. The complementary configurations
 of inner tubular sleeve 18 and bore 64 in end portion 58 prevents the
 inner tubular sleeve 18 from rotating relative to collar assembly 16 and
 outer tubular sleeve 12. First bore portion 60 has a diameter slightly
 less than the diameter of the second bore portion 62. The diameter of
 second bore portion 62 is slightly less than the outer diameter of the
 outer tubular sleeve 12 permitting end 32 of outer tubular sleeve 12 to be
 press fit within second bore portion 62 of collar member 50 and to be
 grippingly retained within same. Outer tubular sleeve 12 is received and
 positioned within collar member 50 such that its end 32 abuts shoulder 66
 defined by the junction of first bore portion 60 with second bore portion
 62 of collar member 50.
 Bottom trigger member 52 is formed from moldable plastic material and is
 generally U-shaped in configuration, as shown in FIGS. 3 and 4, and has a
 pair of spaced apart projections or ears 80 on the inner surface 82 and
 adjacent each outer end 84 thereof. An inwardly directed lip 86 is located
 on the inner surface 82 of bottom trigger member 52 and is positioned
 between each pair of ears 80. The outer surface 88 of bottom trigger
 member 52 is provided with a flattened surface 90 for placement of the
 user's thumb in order to facilitate depressing bottom trigger member 52 to
 adjust the overall length of extension pole 10, as hereinafter described.
 The top trigger member 54 is generally circular in configuration, as shown
 in FIGS. 5 and 6, with a tab 100 adjacent each outer end 102 thereof. An
 angularly extending gap 104 is provided between the ends 106 of the tabs
 100. A recess 108 that is sized so as to receive an ear 80 on bottom
 trigger member 52 is provided on either side of each tab 100. In addition,
 an elongated recess 110 that is sized so as to receive inwardly directed
 lip 86 on bottom trigger member 52 is provided in each tab 100. Locking
 pin 56 is provided within a blind bore 112 in the inner surface 114 of top
 trigger member 54 and is positioned so as to be substantially oppositely
 disposed to angularly extending gap 104. Alternatively, locking pin 56 can
 be received within a through bore (not shown) in top trigger member 54 and
 can be positioned and retained therein so as to be substantially
 oppositely disposed to angularly extending gap 104. The end 116 of locking
 pin 56 is chamfered, as shown in FIG. 7, providing a pilot or guiding
 surface for same.
 The top trigger member 54 is formed from a flexible plastic material and
 has an inner diameter slightly less than the outer diameter portion 120 of
 collar member 50 which is positioned adjacent first bore portion 60
 thereof, as shown in FIG. 2. In this manner, the top trigger member 54 can
 be slipped over outer diameter portion 120 of collar member 50 and is
 grippingly retained thereon. The diameter of outer diameter portion 120 is
 slightly less than the immediately adjacent diameters of end portion 58
 and second bore portion 62 of collar member 50 forming shoulders 122 and
 124, respectively, which minimize the possibility of any foreign material
 becoming entrapped between trigger members 52, 54 and outer diameter
 portion 120 of collar member 50. Outer diameter portion 120 of collar
 member 50 has a bore 126 therethrough for receipt of locking pin 56 in top
 trigger member 54. Bore 126 is aligned with apertures 36 in inner tubular
 sleeve 18. After top trigger member 54 has been received on outer diameter
 portion 120 of collar member 50, bottom member trigger member 52 is press
 fit into top trigger member 54 causing each oppositely disposed ear 80 on
 each end 84 of bottom trigger member 52 to be received within a
 complementary elongated recess 108 on top trigger member 54 and also
 causing inwardly directed lip 86 adjacent each end 84 of bottom trigger
 member 54 to be received within its complementary elongated recess 110
 provided in tab 100 on top member 54, as shown in FIG. 7. In this manner,
 the ears 80 and the inwardly directed lip 86 on the bottom trigger member
 52 interlock with the complementary recesses 108 and 110 on top trigger
 member 54 causing the bottom trigger member 52 and the top trigger member
 54 to be joined and move as a unit. In addition, since top trigger member
 54 grippingly engages outer diameter portion 120 of collar member 50 and
 since bottom trigger member 52 is U-shaped rather than circular in
 configuration, the interlocking engagement of these members causes a gap
 128 to be created between the inner surface 82 of bottom trigger member 52
 and the adjacent surface defining the outer diameter portion 120 of collar
 member 50.
 In order to adjust the length of the extension pole 10, the surface 90 on
 bottom trigger member 52 is pressed laterally inwardly against outer
 tubular sleeve 12 causing the gap 128 to close and causing the top trigger
 member 54, which is formed from flexible plastic material, to move
 laterally outwardly with respect to collar member 50 resulting in locking
 pin 56 in top trigger member 54 being retracted from aperture 36 in inner
 tubular sleeve 18 through bore 126 in outer diameter portion 120 of collar
 member 50. The distance of lateral movement of the trigger members 52, 54
 is less than the height of shoulders 122, 124 on collar member 50
 minimizing the possibility of any foreign material passing between the
 trigger members 52, 54 and the shoulders 122, 124 and becoming entrapped
 between the trigger members 52, 54 and the outer diameter portion 120 of
 the collar member 50. The inner tubular sleeve 18 can then be
 telescopically adjusted within outer tubular sleeve 12 until the
 approximate desired length of the extension pole 10 has been attained. If
 the bottom trigger member 52 is then released, the gap 128 opens causing
 the top trigger member 54 to move laterally inwardly with respect to
 collar member 50 resulting in the chamfered end 116 of locking pin 56
 contacting the outer surface of inner tubular sleeve 18. Further
 telescopic adjustment of inner tubular sleeve 18 within outer tubular
 sleeve 12 causes the locking pin 56 to be received within the closest
 aperture 36 provided within the inner tubular sleeve 18 resulting in the
 inner tubular sleeve 18 being locked within the outer tubular sleeve 12 at
 the approximate desired length of the extension pole 10. (The chamfered
 end 116 of locking pin 56 acts as a pilot or guiding surface which assists
 in the receipt of the locking pin 56 in the closest aperture 36.) The
 circular flanged surface 42 on end cap 20 prevents the inner tubular
 sleeve 18 from being inadvertently removed from within the outer tubular
 sleeve 12 during the telescopic adjustment process. In this manner, the
 length of the extension pole 10 can be easily adjusted and, when adjusted,
 the length is retained by the locking pin 56 in the top trigger member 54
 being received in the appropriate aperture 36 in the inner tubular sleeve
 18.
 The locking mechanism of the present invention provides a number of
 advantages over prior art locking mechanisms. For example, the locking
 mechanism utilizes a minimum number of components which, because of their
 design, makes the locking mechanism less susceptible to paint being
 entrapped therein. In addition, the components comprising the locking
 mechanism (bottom trigger member 52, top trigger member 54 and locking pin
 56) are relatively inexpensive and easy to produce and assemble. Also, the
 components comprising the locking mechanism are very durable, however,
 they can be easily replaced, if necessary.
 An alternate embodiment of the locking mechanism of the present invention
 is shown in FIGS. 8 through 11 which illustrate a collar assembly 130
 (locking mechanism) attached to the end of the outer tubular sleeve 12 of
 the extension pole 10. In this embodiment, the collar assembly 130 is
 comprised of a collar member 132 and a trigger member 134 having a locking
 pin 136 therein. The trigger member 134 is of a one-piece, rather than a
 two-piece, construction, is formed from flexible plastic material, and is
 received over the collar member 132. The outer portion of trigger member
 134 is generally oval in configuration, but its inner portion, shown
 generally by the numeral 138, is circular in configuration. The inner
 portion 138 of the trigger member 134 has a circumferential slot 140
 therein which terminates in a U-shaped slot 142 defining circumferential
 tangs 144. The trigger member 134 is positioned on the collar member 132
 such that the inner portion 138 grippingly engages the outer diameter of
 the collar member 132 permitting the locking pin 136 to be positioned
 within a bore 146 in collar member 132 and received in an aperture 36 in
 inner tubular sleeve 18. The circumferential slot 140, U-shaped slot 142
 and circumferential tangs 144 in the inner portion 138 provide flexibility
 to the inner portion 138 of the trigger member 134 permitting lateral
 outward movement of the trigger member 134 with respect to the collar
 member 132. In order to adjust the overall length of the extension pole
 10, surface 148 on trigger member 134 is pressed inwardly, as shown in
 FIG. 11, causing trigger member 134 to move laterally outwardly with
 respect to collar member 132 resulting in locking pin 136 being retracted
 through bore 146 in collar member 132. The inner tubular sleeve 18 can
 then be telescopically adjusted within outer tubular sleeve 12 until the
 approximate desired length of the extension pole 10 has been attained. If
 the trigger member 134 is then released, the trigger member 134 will move
 laterally inwardly causing the locking pin 136 to be received in the
 closest aperture 36 provided in inner tubular sleeve 18 resulting in inner
 tubular sleeve 18 being locked within the outer tubular sleeve 12 at the
 approximate desired length of the extension pole 10.
 Certain modifications and improvements will occur to those skilled in the
 art upon reading the foregoing. It should be understood that all such
 modifications and improvements have not been expressly set forth herein
 for the sake of conciseness and readability, but are properly within the
 scope of the following claims.