US2444758A - Cleaning implement - Google Patents

Cleaning implement Download PDF

Info

Publication number
US2444758A
US2444758A US790967A US79096747A US2444758A US 2444758 A US2444758 A US 2444758A US 790967 A US790967 A US 790967A US 79096747 A US79096747 A US 79096747A US 2444758 A US2444758 A US 2444758A
Authority
US
United States
Prior art keywords
handle
slot
socket
sleeve
mop
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US790967A
Inventor
Jan H Stillbach
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US790967A priority Critical patent/US2444758A/en
Application granted granted Critical
Publication of US2444758A publication Critical patent/US2444758A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • AHUMAN NECESSITIES
    • A47FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
    • A47LDOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
    • A47L13/00Implements for cleaning floors, carpets, furniture, walls, or wall coverings
    • A47L13/10Scrubbing; Scouring; Cleaning; Polishing
    • A47L13/20Mops
    • A47L13/24Frames for mops; Mop heads
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T279/00Chucks or sockets
    • Y10T279/17Socket type
    • Y10T279/17888Tang offset within socket
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T403/00Joints and connections
    • Y10T403/70Interfitted members
    • Y10T403/7005Lugged member, rotary engagement
    • Y10T403/7007Bayonet joint
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T403/00Joints and connections
    • Y10T403/70Interfitted members
    • Y10T403/7075Interfitted members including discrete retainer
    • Y10T403/7077Interfitted members including discrete retainer for telescoping members
    • Y10T403/7079Transverse pin

Definitions

  • the ypresent invention-' relates tof improvements ⁇ inecleaning implements, such asf-mopsfscrubbing vbrushes, brooms,.sque egees, etc.,- and'morerpar- Y ticularlyto means for-coupling-orA unitingv .cleaning heads With'- the handleX ofi-the implement.
  • One of ,the objects of the present invention is to provide an improved coupling between the head of a cleaningimplement.and..the,handle thereof whereby mop heads', brush bodies, broom heads,
  • Anotherobject-ofthe invention is tio-provide a angular adjustment of thecleaning head on the handle.
  • Figure 1 is a ⁇ perspective View of the improved handle and a mop head mounted thereon;
  • Fig. 2 is a central longitudinal section taken through the handle, the mop head, and the coupling between the said two elements;
  • Fig. 3 is an exploded view, in perspective, showing the several parts of the cleaning implement.
  • the #sleeve is*foscillatably-m :nuntedon.v the @handle by ,.iineansfof az-lug I6, AwhichV extends through. V'a1-slot I 'Lin ,the .handle and; carries afgspring 7 I 8; which is :l .disposed within theV socket. 'e
  • The: -purposeyof i .this-aspiring is;,.tol prevent, ⁇ accidental. turning Aof :j the; locking? sleeve when l 'the.. in iplementt is .g in
  • the mop head I4 comprises two clamping members 20 and 2I, between which the mop material 22 is held.
  • 'I'he mop material consists of a suitable number of strands, bound along their longitudinal center between fabric strips 23, which are fastened together, preferably, by sewing.
  • the mop material is folded upon itself as shown in Figs. 1 and 3 of the drawings and placed between the clamping members 20 and 2I.
  • the clamping member 20 is, preferably, made of wire and includes a substantially vertical portion 24 that is screwthreaded at its free end.
  • the vertical portion 24 is passed through holes 25 in the fabric strips and also through a hole 26 in the clamping member 2I, it extending through and above the stem I3 already referred to.
  • the stem I3 is immovably fixed to the clamping member 2I, its pin I2 extending laterally thereon.
  • a knurled nut 21 engages the threads of the vertical lportion of the clamp 20, being adapted to i0 indicates the handle of the implement, which, 55 bear against the free end of the stem I3, whereby the members 20 and 2l are held in clamping positions upon the mop material.
  • the locking sleeve l5 When it is intended to assemble the mop head with the handle, rst the locking sleeve l5 is moved upon the handle so that the vertical leg of its bayonet slot is brought into alignment with the handle slot Il.
  • the ypin l2 is then fitted into the last-mentioned two slots and the stem I3 .shifted into thehandle socket'untilr the pin I2 is in alignment with the horizontal portion of the bayonetslot.
  • the locking sleeve is then turned so that the pin I 2 is brought into the horizontal portion of the bayonet slot, whereby the implement is ready for use.
  • the spring I8 prevents accidental movement of the sleeve while the implement isv in operation

Landscapes

  • Cleaning Implements For Floors, Carpets, Furniture, Walls, And The Like (AREA)

Description

July 6, 1948. J. H. STILLBACH 2,444,758
' CLEANING IMPLEMENT Filed Dec. 11, 1947 Patented July 6, 1948 4 Claims.
l f The ypresent invention-'relates tof improvements `inecleaning implements, such asf-mopsfscrubbing vbrushes, brooms,.sque egees, etc.,- and'morerpar- Y ticularlyto means for-coupling-orA unitingv .cleaning heads With'- the handleX ofi-the implement.
Mechanisms-for detachably'lv'mounting a-.mop
as known, ithas beenl-heretoforethe lgeneral practice to so construct the head and-1thehandle that' onlyahead of a specific type-isadapted to be mounted upon` said handle.
One of ,the objects of the present invention is to provide an improved coupling between the head of a cleaningimplement.and..the,handle thereof whereby mop heads', brush bodies, broom heads,
v squeegees, and the like"may..beinterchangeably atta-ched to a universal handlegthatis togsay, so to constructthe.handlethat practically all cleaning implement heads used in a normal household"il mayf-.be mounted on thehandle, as occasionv of -the -use 'of these implementsfarises.
= Anotherobject-ofthe invention is tio-provide a angular adjustment of thecleaning head on the handle.
With these and other-objects in View, which will I`more fully appear `-as the nature fof thel invention Yisvbetterunderstood, the-:sameYA consists in the combination arrangement and construction of parts hereinafter described, pointed out in the appended claims and illustrated in the accompanying drawings, it being understood that many changes may be made in the size and proportion of the several parts and details of -construction within the scope of the appended claims, without departing from the spirit or sacrificing any of the advantages of the invention.
One of the many possible embodiments of the handle of the implement and of the cleaning head is illustrated in the accompanying drawings, in which:
Figure 1 is a `perspective View of the improved handle and a mop head mounted thereon;
Fig. 2 is a central longitudinal section taken through the handle, the mop head, and the coupling between the said two elements; and
Fig. 3 is an exploded view, in perspective, showing the several parts of the cleaning implement.
Referring now to the drawings, the numeral .in-'the case illustrateds finstancerf the said :handle .may:.;bef:inf;lthe
tached an open ferrule,ypriojec,ting a..s11b$tantial :idistancebelowf theustaff so as to fformaI socket in @the handle, f c, .In a the .caser illustrated, :the 1 tubular handle isopen atitslower end, andthe-,lattenwill .be :referred to,- hereinafter 1 as a .sock-et. rf Fromthe open end of the handle extends upwardlyvauslot ii I Vrunningparalleli with;y the .longitudinali axis ..ofthe..tube.and:serving toa receive aafpin-IZ-on a .cylindricalstemiffl3., which ispca-rried,=in ama-nner hereinafter to be described," by etheffmop- 'head I4. Surrounding the open end'lofthe .itube is a locking sleeveIE, part offwhichis knurled to 1 ,facilitateA manual operationofnthe 1 same. The #sleeve is*foscillatably-m :nuntedon.v the @handle by ,.iineansfof az-lug I6, AwhichV extends through. V'a1-slot I 'Lin ,the .handle and; carries afgspring 7 I 8; which is :l .disposed within theV socket. 'e The: -purposeyof i .this-aspiring is;,.tol prevent,` accidental. turning Aof :j the; locking? sleeve when l 'the.. in iplementt is .g in
`coupling-elementwhich iscapable of being-at-r` I tachedv to A=all- -`of the cleaningeelements above'i" "referred to, lsaid-couplingwelement being fso -con- `structed that it -mayvebe immovably mounted-on a aoperation. l11m.the.flocking#sleeve isf-formed a tbayonetxslot I 9;;y ,thevvertical glegofwhichfextends .from11the-:lower eend of '.-t-he docking, sleeves and merges/into a `horizontal leg; f Thelength of said 1 `horizontaleleg corresponds substantially to f that ofzthe handle slotl 15 andtheflatter; isy so; located @so .that it .permits :the :vertical -leg-,f.of the bayonet Mslottoloe brought into alignmenttwith.thehandle be ttedsimultaneouslyintoatheslot I I,:.and.;the
bayonet slot I9.
The mop head I4 comprises two clamping members 20 and 2I, between which the mop material 22 is held. 'I'he mop material consists of a suitable number of strands, bound along their longitudinal center between fabric strips 23, which are fastened together, preferably, by sewing. The mop material is folded upon itself as shown in Figs. 1 and 3 of the drawings and placed between the clamping members 20 and 2I. The clamping member 20 is, preferably, made of wire and includes a substantially vertical portion 24 that is screwthreaded at its free end. The vertical portion 24 is passed through holes 25 in the fabric strips and also through a hole 26 in the clamping member 2I, it extending through and above the stem I3 already referred to. The stem I3 is immovably fixed to the clamping member 2I, its pin I2 extending laterally thereon. A knurled nut 21 engages the threads of the vertical lportion of the clamp 20, being adapted to i0 indicates the handle of the implement, which, 55 bear against the free end of the stem I3, whereby the members 20 and 2l are held in clamping positions upon the mop material.
When it is intended to assemble the mop head with the handle, rst the locking sleeve l5 is moved upon the handle so that the vertical leg of its bayonet slot is brought into alignment with the handle slot Il. The ypin l2 is then fitted into the last-mentioned two slots and the stem I3 .shifted into thehandle socket'untilr the pin I2 is in alignment with the horizontal portion of the bayonetslot. The locking sleeve is then turned so that the pin I 2 is brought into the horizontal portion of the bayonet slot, whereby the implement is ready for use. As mentioned heretofore, the spring I8 prevents accidental movement of the sleeve while the implement isv in operation,
It is obvious that other cleaning elements, such as scrubbing brushes, squeegees and the like may be provided with the stem i3 above referred to, the latter being adapted tobe fastened to mop ramea'backs of brushes, .or blade carrying frames of squeegees, for the purpose of coupling socket in its lower end, of a cleaning material supporting frame col-operating therewith, said '.socketlbein-g provided with-a longitudinal slot running inwardly from its open end, a cylindrical stem mounted upon said frame adapted to be seated in 'saidsocket a laterally extending pin on said stem' for engagement with said slot, a locking sleeve oscillatably arranged on said handle over said'Aso-cket and being provided with va bayonet slot having one leg capable of overlying said kfirst-named slot `and its other leg running 'atright angles theretogwher'eby said pin is prevented from disengagement from said firstnamed slot'when said locking sleeve is turned I so that one' of its legs is brought out of alignment .with saidv first-named slot, and a lspring mounted on said'sleeve and bearing against'the Number f inner surface of said socket to prevent accidental turning of said sleeve on said handle.
2. In a combination according to claim 1, said spring being wholly disposed Within said socket.
3. The combination with a handle having a socket in its lower end, of a cleaning material supporting frame :so-operating therewith, said socket being provided with a longitudinal slot running inwardly from its open end, a cylindrical stemfmounted.uponfsaid frameadapted to be seated in'said socket, 'a laterally extending pin on said stem for engagement with said slot, a locking sleeve oscillatably arranged on said handle over said socket and being provided With a bayonet slot having one leg capable of overlying said rst-named slot and its other leg running at right angles thereto, whereby said pin is prevented frorn disengagement from said first-named slot when said locking sleeve is turned so that one o-f its legs is brought out of alignment with said rstenamed slot, said socket being provided witha slot running at right angles to said rstnarned socket slot, a lug fixed to said sleeve extending through the socket slot which runs at right angles to said rst-named slot, and a spring mounted on said lug and bearing against the inner surface of said socket to prevent accidental turning of said sleeve' on said handle, said lug limiting the oscillating movement of said sleeve on said socket.
4. In ar combination according` to claim 3, said spring being Wholly disposed within said socket.
JAN H. STILLBACH.
REFERENCES CITED 'The following references are of record in the file of this patent:
'UNrTED ySTATES PATENTS Name Date 921,840 Jacobs May 18, 1909 931,327 Manzel Aug. 17, 1909 1,418,184 Trunick l May 30, 1922 1,420,639 Sturgis June 27, 1922 1,494,859 Miller et al May 20, 1924 1,505,318 Berlow Aug. 19, 1924 1,932,099 Cabana Oct; 24, 1933 FOREIGN PATENTS Number y Country Date 245,076 Italy Feb'. 18, 1926 691,732 r France Oct.,24, 1930
US790967A 1947-12-11 1947-12-11 Cleaning implement Expired - Lifetime US2444758A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US790967A US2444758A (en) 1947-12-11 1947-12-11 Cleaning implement

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US790967A US2444758A (en) 1947-12-11 1947-12-11 Cleaning implement

Publications (1)

Publication Number Publication Date
US2444758A true US2444758A (en) 1948-07-06

Family

ID=25152274

Family Applications (1)

Application Number Title Priority Date Filing Date
US790967A Expired - Lifetime US2444758A (en) 1947-12-11 1947-12-11 Cleaning implement

Country Status (1)

Country Link
US (1) US2444758A (en)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2905958A (en) * 1955-05-23 1959-09-29 Duwamish Mfg Co Roofing mop and method of making the same
US3065009A (en) * 1961-11-16 1962-11-20 Harold T Austin Twist-lock rod coupling
US3423781A (en) * 1967-10-25 1969-01-28 Harry H Henson Securement for mop or broom heads
US4441652A (en) * 1982-02-05 1984-04-10 Miyawaki Steam Trap Mfg. Co., Ltd. Exchangeable unit steam trap
US4642837A (en) * 1985-08-20 1987-02-17 The Drackett Company Broom having interlocking components
US5297887A (en) * 1992-08-21 1994-03-29 Williams Stephen R Injection-molded receiver
US5423568A (en) * 1992-10-30 1995-06-13 Takata Corporation Air bag device with an inflator mounting structure
US5427406A (en) * 1992-10-30 1995-06-27 Takata Corporation Air bag device with an inflation mounting structure
US6438784B1 (en) * 2000-09-29 2002-08-27 Chih-Hsin Yu Cleaning device with replaceable head
US6532695B1 (en) * 2000-04-13 2003-03-18 Richard Alvarado Multiple bait structure insect trap
US20040109724A1 (en) * 2002-08-16 2004-06-10 Peter Tiemann Fastening system
US20050004600A1 (en) * 2003-06-11 2005-01-06 Stryker Trauma Gmbh Coupling system for an intramedullary nail and associated instruments
US20060043667A1 (en) * 2004-08-25 2006-03-02 Philip Lawrence Schlaefer Quick-change foosball table rod handles
US20070078460A1 (en) * 2005-08-25 2007-04-05 Robert Frigg Methods of spinal fixation and instrumentation
US20090021122A1 (en) * 2007-07-19 2009-01-22 Bush Industries, Inc. Wall System Having Furniture Modules and Accessories for Attaching and Finishing the Modules
US9366315B2 (en) 2013-11-13 2016-06-14 Timothy T. Tylaska Locking quick connect fitting
CN113905632A (en) * 2019-06-24 2022-01-07 特洛依海伦有限公司 Cosmetic instrument head locking mechanical system
US11293472B2 (en) * 2017-06-26 2022-04-05 Souriau Bayonet-type locking and unlocking system for circular connector with audible indicator

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US921840A (en) * 1907-10-25 1909-05-18 Frank M Jacobs Detachable extension-handle for tools.
US931327A (en) * 1908-03-13 1909-08-17 Mary A Manzel Drill-chuck.
US1418184A (en) * 1920-08-12 1922-05-30 Trunick Charles Screw driver
US1420639A (en) * 1920-12-08 1922-06-27 Save A Handle Products Co Mop head and fastener therefor
US1494859A (en) * 1921-10-03 1924-05-20 Mccrosky Tool Co Quick-change chuck and collet
US1505318A (en) * 1921-01-11 1924-08-19 Berlow Harry Attachment device
FR691732A (en) * 1930-03-11 1930-10-24 New removable handle for brooms, brushes, dusters and similar items
US1932099A (en) * 1931-10-30 1933-10-24 Liquid Veneer Corp Handle connection

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US921840A (en) * 1907-10-25 1909-05-18 Frank M Jacobs Detachable extension-handle for tools.
US931327A (en) * 1908-03-13 1909-08-17 Mary A Manzel Drill-chuck.
US1418184A (en) * 1920-08-12 1922-05-30 Trunick Charles Screw driver
US1420639A (en) * 1920-12-08 1922-06-27 Save A Handle Products Co Mop head and fastener therefor
US1505318A (en) * 1921-01-11 1924-08-19 Berlow Harry Attachment device
US1494859A (en) * 1921-10-03 1924-05-20 Mccrosky Tool Co Quick-change chuck and collet
FR691732A (en) * 1930-03-11 1930-10-24 New removable handle for brooms, brushes, dusters and similar items
US1932099A (en) * 1931-10-30 1933-10-24 Liquid Veneer Corp Handle connection

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2905958A (en) * 1955-05-23 1959-09-29 Duwamish Mfg Co Roofing mop and method of making the same
US3065009A (en) * 1961-11-16 1962-11-20 Harold T Austin Twist-lock rod coupling
US3423781A (en) * 1967-10-25 1969-01-28 Harry H Henson Securement for mop or broom heads
US4441652A (en) * 1982-02-05 1984-04-10 Miyawaki Steam Trap Mfg. Co., Ltd. Exchangeable unit steam trap
US4642837A (en) * 1985-08-20 1987-02-17 The Drackett Company Broom having interlocking components
US5297887A (en) * 1992-08-21 1994-03-29 Williams Stephen R Injection-molded receiver
US5423568A (en) * 1992-10-30 1995-06-13 Takata Corporation Air bag device with an inflator mounting structure
US5427406A (en) * 1992-10-30 1995-06-27 Takata Corporation Air bag device with an inflation mounting structure
US6532695B1 (en) * 2000-04-13 2003-03-18 Richard Alvarado Multiple bait structure insect trap
US6438784B1 (en) * 2000-09-29 2002-08-27 Chih-Hsin Yu Cleaning device with replaceable head
US6971847B2 (en) * 2002-08-16 2005-12-06 Siemens Aktiengesellschaft Fastening system
US20040109724A1 (en) * 2002-08-16 2004-06-10 Peter Tiemann Fastening system
US20110078887A1 (en) * 2003-06-11 2011-04-07 Stryker Trauma Gmbh Method for coupling an intramedullary nail and associated instruments
US20050004600A1 (en) * 2003-06-11 2005-01-06 Stryker Trauma Gmbh Coupling system for an intramedullary nail and associated instruments
US8337505B2 (en) 2003-06-11 2012-12-25 Stryker Trauma Gmbh Method for coupling an intramedullary nail and associated instruments
US7901410B2 (en) * 2003-06-11 2011-03-08 Stryker Trauma Gmbh Coupling system for an intramedullary nail and associated instruments
US20060043667A1 (en) * 2004-08-25 2006-03-02 Philip Lawrence Schlaefer Quick-change foosball table rod handles
US20070078460A1 (en) * 2005-08-25 2007-04-05 Robert Frigg Methods of spinal fixation and instrumentation
US7909830B2 (en) * 2005-08-25 2011-03-22 Synthes Usa, Llc Methods of spinal fixation and instrumentation
US20110152940A1 (en) * 2005-08-25 2011-06-23 Robert Frigg Methods of spinal fixation and instrumentation
US8808296B2 (en) 2005-08-25 2014-08-19 DePuy Synthes Products, LLC Methods of spinal fixation and instrumentation
US20090021122A1 (en) * 2007-07-19 2009-01-22 Bush Industries, Inc. Wall System Having Furniture Modules and Accessories for Attaching and Finishing the Modules
US9366315B2 (en) 2013-11-13 2016-06-14 Timothy T. Tylaska Locking quick connect fitting
US11293472B2 (en) * 2017-06-26 2022-04-05 Souriau Bayonet-type locking and unlocking system for circular connector with audible indicator
CN113905632A (en) * 2019-06-24 2022-01-07 特洛依海伦有限公司 Cosmetic instrument head locking mechanical system
EP3986201A4 (en) * 2019-06-24 2023-01-25 Helen of Troy Limited Beauty tool head locking mechanism

Similar Documents

Publication Publication Date Title
US2444758A (en) Cleaning implement
US3362037A (en) Disposable mop
US3778860A (en) Mop frame assembly
US4494268A (en) Paint brushes
US2127886A (en) Stick-handled appliance for the care of floors and stairs
US4769869A (en) Multiple use cleaning utensil
US3713184A (en) Mop with interchangeable heads
US20040148721A1 (en) Bottle wash and dry device
WO2019040687A2 (en) Combination mop and broom
US5359749A (en) Paint brush with replaceable head
US2516195A (en) Fountain toothbrush
US3537123A (en) Cleaning device with interchangeable head
US3188671A (en) Convertible dust and floor mop
FR2282252A2 (en) Floor-cleaning mop with wringer mechanism - has elongate cloth head held secure in middle by circular holder and rod
US1998278A (en) Mop head and swab
US1921921A (en) Sponge washer
US2712144A (en) Manually releasable mop head having resiliently biased clamping bars
US2559722A (en) Mop head holder
US1583358A (en) Cleaning appliance for floors and other surfaces
US1224524A (en) Mop-head.
US2138012A (en) Quill brush holder
US3849825A (en) Mop head support tool
US3372418A (en) Pivoting brush
WO2007097894A2 (en) Duster with handle insert
US2759211A (en) Dishes and window cleaning device