US3158707A

US3158707A - Door interlock

Info

Publication number: US3158707A
Application number: US224422A
Authority: US
Inventors: William C Files
Original assignee: McGraw Edison Co
Current assignee: McGraw Edison Co
Priority date: 1962-09-18
Filing date: 1962-09-18
Publication date: 1964-11-24
Anticipated expiration: 1981-11-24

Description

Nov. 24, 1964 w. c. FILES 3,158,707

DOOR INTERLOCK 1N VEN TOR.

Nov. 24, 1964 Filed Sept. 18, 1962 w. c. FILES 3,158,707

DOOR INTERLOCK 4 Sheets-Sheet 2 Wmmfgw 4 Sheets-Sheet 5 W. C. FILES DOOR INTERLOCK Nov. 24, 1964 Filed Sept. 1B 1962 @,Mlw

w. c. FILES DooR IN'TERLOCK Nov. 24, 1964 4 Sheets-Sheet 4 Filed Sept. 18, 1962 I ll United States Patent O 3,l58,77 Dflll INTERLCK William C. Files, Cin i nati, Ohio, assigner to McGraw- Edison Company, lill., a corporation or Delaware Filed Sept. ld, lilo-2, No. 224,422 ldfClaiins. (till. Enth-63h54) This invention relates to novel and improved safety interlock means for the door or doors of a rotatable cylinder for laundry machines such as washers or extractora As ,is known to those skilled in this art a conventional commercial washer includes a iixed housing usually termed a tub, within which a work container or cylinder 'is rotatable on a shaft. The shaft end is journalled in earings in the tub end walls, and one end of the shaft extends outwardly and .is driven by power means located on or near the tub.

rl`he tub and the cylinder are provided with respective doors which are registrable for work loading and unloading. After a washing, rinsing and possibly extracting .operation the cylinder i-s stopped; the ytub door or doors in the embodiment herein later described and shown there are two compartments Separated by a ,horizontal diametrical partition. Each compartment of course has its respective door or doors. ln loading, the doors of one cylinder compartment are opened, the load inserted, and the doors are closed. The cylinder is then rotated through l80 and the operation is repeated with the other cornpartment.

Several cylinders may sometimesbe placed in end-toend juxtaposition, in the interest of space conservation or because they can be driven from the same motor, us ing `the same control console or panel, and in the following Ldrawings l show two such cylinders. lt is to be understood however that the invention is individually adaptable to a single cylinder.

Since the present invention will be described in its adaptation to the latching and locking means for a rotatable cylinder door, the door for the tub will not be shown, and can be any suitable design, conventional or otherwise.

An object of the pesent invention is to provide novel and improved cylinder doorlatching and locking means.

A further object of the invention is to provide, in cornbination with the latchinU and locking means mentioned in the last preceding paragraph, means insuring eihcient safety yfeatures which prevent rotation of the cylinder until its door or doors are closed and locked.

Other objects and advantages will be apparent ytrom a study ofthe following description of one embodiment of the invention, n conjunction with the accompanying drawings, in which:

FIG. l is a perspective view as seen from the right front corner, showing a washing machine assembly einbodying myk invention;

F182 is an enlarged fragmentary perspective view of a portion of FIG. l, but with the cylinder doors closed and locked;

FIG. 3 is an elevational view of a fragmentary detail portion of a Cylinder door locking device as shown in FIG. 2;

Patented Nov. 24, 1964 FIGS. 4 and 5 are sectional views taken respectively on the lines l-d and 5 5 of FIG. 2;

PEG. 6 is a sectional View taken on the line 6-6 of HG. 5;

FlGS. 7 and 8 are sectional views taken respectively on the lines '7--7 and of FIG. 4;

FlG. 9 is a sectional view, greatly enlarged, taken on the line lll-tl of FlG. l;

FIG. lt) is a view, similar to FIG. 9, but showing some parts in a diilerent operating position;

FlG, ll is an end elevational view as seen mainly from the position of the line lll-ll of FlG. l0.

Referring first to lil-G. l, there is sho-wha laundry unit comprising two cylindersdesignated generally by the arrows 29 and 2l. They are disposed in end-to-end relationship, and are identical in substantially allrespects. This is found to be an efficient arrangement from the standpoint oiloor space conservation, a common motor drive, a common control panel, common water and supply feed lines, etc. he invention can be adequately shown and described in connection with one cylinder, and in this description and the drawings lreference will be made only to cylinder 2li. f

This cylinder E@ is supported for rotation in a xed tub, of which we show the supporting end heads and 23. The cylinder is divided into two generally `sernicylindrical compartments by a partition 2d. .Each such cornpartinent'has a door opening which can beclosed by two cooperatin'g curved'- doors ZS and 26 which in the position of FlG. l are respectively hinged on opposite upper and lower edges of the opening. in closing they swing to edge abutment, as shown for example in FIGS. 2 and 7. For loading and unloading the compartment shown as accessible in FIG. 1 the cylinder can'be rotated so that partition 2d tilts downwardly and outwardly for unloading, or slightly upwardly buty inwardly for rnechanical loading. The tub door opening isllarge enough to permit necessary leeway in cylinder swing for these operations. The central drive sh aft in housing ZTis driven by a belt Ztl from a motor and gear reduction assembly 29, this arrangement being'conventional.

Proceeding now to FIG. 2 and subsequent gures, each door part is provided with ,two oppcsitely movable latch bolts which, when in latching position, are movably carried on the door and can be advanced to aseat in a retainer in theidoor jamb. FG. 4 shows one such bolt 32 movable in a trough or well in the door, its tip end being Seatable in a retainer 33. The mid portion of the bolt slides in an aperture in a guide block carriedion the door. The apertures in the guide block and retainer come into registry when the door is in closed position.

The bolt 32 is operated by a toggle arrangement cornprising an actuator lever or handle 34 which is pivoted at S55 to the bolt, and at a spaced point is pivoted to a pilot link 37 ywhich carries a sleeved extension 37a serving as a socket for a plunger 3S. The plunger has an extension 3tlg which positions a compression spring 39 in the socket. The rear end of the plunger ispivoted at 40 on a lpin extending across the well in which the bolt operates. It will be noted that movement or the operating lever between the full line position and the broken line position or FIG. 4 provides an over-center snapaction operation wherein the pivot 3.6 moves across the line connecting the pivots 35 and dit. The spring 39 provides a bias urging the linkage away from the said center line, both in the direction of bolt advance for latching and bolt withdrawal for unlatching.

FIG. 2 shows four latch handles or levers 34, 34a, 34h and 3de for four respective bolts of the type just described. They are nested in their respective troughs in the four door sections, and in door locked position the snaar/'ov handles are approximately in the plane of the peripheral cylinder door wall (FIGS. 2 and 4). The trough or well previously referred to has a lower level 44 enclosed by the door wall 25. This partition is slotted at d6 to permit operation of the handle 34. The latch bolt 32 and toggle mechanism are in the trough portion 44 and the handle 3d and further associated mechanism are above door wall 25. The roller 47, mounted at the end of trough 44, serves as a fulcrum for 4the inclined end of handle 34 in exerting force to withdraw the bolt 32.

The purpose of further associated mechanism is to retain the latch handles 3ft, 34a, etc., in latching position and therefore provide a positive lock. This prevents the handles from flying outwardly under the influence of centrifugal force when the cylinder is rotating. The means just mentioned also prevents energization of the driving motor until after the doors are securely latched and locked, as will appear.

I have provided a clamping bar 43 which is slidable .over the ends of a pair of latch handles to hold them in door latched position. It includes a transverse portion 4S and two ends i9 `and 5d which have toes 5l and 52 slidable under retaining clips and 54, the clips being welded or otherwise fixed to the respective

cylinder door walls

25 and 26. Clip S3 is longer than clip 545 so that movement of clamping bar it@ to clear the handle ends will also clear toe 52 from clamp 54 while retaining toe 51 under clip 53. This permits the

doors

25 and 26 to be opened and closed when the clamping bar ld clears vfrom under clip 54. Clamping bar 48 by itself has the function of a latch since, when in position under clips 53, 54, it prevents or opposes opening swing of the door halves.

The opposed clamping bars 43 and 58 (FIG. 2), each of which is capable of locking two handles, are operated by a linkage now to be described. Directing attention to FIGS. 2, 3, and 4 it will be noted that clamping bars d8 and 5S carry

locator brackets

59 and 69 of hook-like form having longer legs 59a and 69a, transverse portions 59b and Gibb, and shorter legs 59e and elle. These legs pass through bridged guides ola, ole and 62a, 62e which are carried on the respective reinforcing ribs 65, 65o, 6d and 64a on the periphery of the door halves. lt can be seen in FIG. 3 tha-t the short legs 59a and 60a have inclined sides 59d and @iid which cooperate with the fixed cam faces old, 62d to give a wedged seat for accurately locating the iinal positions of brackets 59 and 6i) when the clamping bars 48 and 5S are moved to their handleretaining position. The locator bracket on clamp bar carrier 59 also helps to hold the door halves in closed position when the leg 555e is engaged in guide 61C.

Midway between the brackets 59 and n@ the door wall 25 carries a bushing 63 which is bored to receive a rotary stud 69. This stud is stepped to provide a supporting shoulder 69a which rests on the partition 25, and the tip end of the stud @9b is threaded and extends through bushing 68 to permit application of a Washer 7@ and nut 7l. The structure is well shown in FIG. 5. The nut 7l is tightened until it engages a shoulder 69g on the unthreaded portion of the stud, which portion is somewhat longer than the bushing 68, so that the nut can be pulled up tightly and the stud' can still be rotated.

This rotary stud 69 has an upper disc portion 69e which has pivotal connections at '72 and 73 respectively with links '74 and 75. These links in turn are pivoted at '76 and '77 to

respective brackets

59 and 6@ previously described. Obviously, clockwise movement of the rotary stud will swing the links from the position shown in FIG. 2, which is the latched position, to that shown in FIG. 3, which is the unlatched position.

An additional safety feature is shown in FIGS. 3 and 4. It comprises the cross bar Sil which is carried on an extension rod 8l fixed at one end to the clamping bar 4S, and at its other end is slidably fitted in a bore 82 in a xed bracket 33. Referring to FIG. 3, wherein one latch handle 34 is shown in its latching position and the other latch handle 34a is in unlatched (raised) position, it is of course possible to turn the rotary stud 69 and advance clamping bar 48 to the left to clamping position. Handle 34a however is in unlatched position. Handle 34a cannot now be swung down because its pivot pin extension 36 will strike cross bar titl and the handle will remain up so that it will be apparent to the operator that the clamping bar 48 must be withdrawn to the right (FlG. 3) to per-mit lowering of handle 34a, after which the clamping bar can be properly moved to a position Where it clamps both handles 34 and 34a. FIG. 2 shows the respective clamping bars 48 and 53 in their proper handleclamping positions.

Operation of the clamping linkage will now be described. FIGS. 5 and 6 show a handwheel 85 having a boss 85a to which is attached a key retainer 86 having a finger or key 87 extending therefrom. The key retainer S6 has a depending projection or locator 86a which enters a central bore in the rotary stud 69. As best seen in FIGS. 2, 3 and 6 the rotary stud is slotted at 69d to receive the key 37 whereby, when the handwheel is pushed down to engage the key in the slot7 and the Wheel is turned, the clamping linkage is operated. For a purpose soon to appear I have provided a fixed locator ring 90 which is carried on door wall 25 by means of bosses 9i and cap screws 92 (FIG. 5). This ring has a slot a which permits the downward insertion of the key finger 87 only at this point.

it may be here stated that the registration of the slot 9Go', in the locator ring with the slot 96d in the rotary stud occurs only when the clamping bars 43 and 5S have been moved to handleretaining position so that in this position the handwheel can oe removed, and later reinserted for unlocking. When the handwheel is turned to unlock the clamping bars the key 37 has been rotated to underlie the overhang of ring 90, and the handwheel remains in place as long as the clamping bars remain unlocked. As shown in FiG. l, the handwheels 85 are retained on and carried with the open doors.

FIG. 5 shows ejector' mechanism which serves a double purpose. In the rst place it induces removal of the handwheel and key-retainer assembly when the door has been locked as above described by turning the handwheel until slots @da and 69d are brought to registry. At this location the key i7 has come to Contact with a plunger 93 which is impelled upwardly by a spring 94 so that it urges the key and handwheel up to a non-operating position, facilitating removal of the handwheel and key assembly. Normally the plunger is held down by the unslotted portion of disc 69. FIGS. 2 and 3 show that disc 69 is cut-out at 69e to permit upward movement of plunger 93. In the second place, and of more importance, when the handwheel is removed the plunger 93 pushes up through the cut-out @e in disc e@ and thereby locks disc 69 and its connected toggles, etc. This prevents accidental reverse rotation of disc o9 from jarring or vibration during cylinder rotation.

With the apparatus so far described, therefore, after both compartments of FIG. 1 have been loaded the doors and 2o are closed, the several latch handles are moved down to insert respective bolts in their retainers, the handwheels carried in the doors are turned to move their respective clamping bars to handle-retaining position, and the wheels can now be removed. They must be removed to permit closing of the outer tub doors.

In the system shown herein the cylinders cannot yet be operated because of additional safety feature now to be described. Considering FlGS. l and Il, there are shown certain terminal fragmentary portions of an electric circuit including lines 95 and 96 which are continued to the switch housing 97 in FIG. l1. This could of course be a threephase circuit with one additional line. The connection to the supply line is indicated at Ll, L2 in FIG. l1. The complete electrical circuit need not be I shown since it can easily be supplied with even rudimentary electrical skill. Depression of button 98 operates a micro-switch in housing 97 to energize the motor drive 29 (FIG. 1). Operation of this switch is achieved by means of the handwheel and key assembly already described.

Referring now to FlGS. l, 9, and 11 kl show the handwheel S5, `with its key retainer 86 and key 87 using the same reference characteristics asin the previous descriptionand drawings. lIt is operated as follows. A cupped housing 100 has side walls 161, -1tl2 and a bottom Wall v103. A sleeve 11M-is welded in an aperture in the bottom wall. A collar 165 surrounds another aperture in the -top wall 166. This cupped assembly is carried on the front panel 107 of the control console 198,111@ .1. ,A depressiblebushing' 11@ is slidable in the-sleeve 111114 and is `biased upwardly by compression spring 1-11. Upward movement of the bushing 11i? is limited by abutment of a collar 112 which abuts the sleeve 194 and which is fixed on bushing 11) by a setscrew 113. Collar k112 carries a switch operating linger 116 which can be rotated to a position where it contacts and depresses the switch button 9S hereinabove y mentioned.

lnop'eration the handwheel vkey retainer Se is inserted through collar 135 whiclhfhas aslot 117 to permit ,passage of key 8'7. The locatorv pin Sea enters the aperture in bushing 116, and key 87 enters a slot 118 in the upper discoidal portion'llltla ofthe bushing. A segmental undercut 1,19, of 90 kdegrees extent, has been machined onthe under surface of part 10S having at one radial end the slot 117 and atits other :radial end a groove 120. When the handwheel is inserted and depressed against spring 111, the'key 37, which has a lower edgey portion inslot 118, lis :rotated along the segmental cut-away 119 until thekey reachesthe end of itsswing and comes toregistry .with groove 12u, at which time spring 111 pushes bushing 11u and causes key 87 to snap into a seat in groove .120. At this point (FG. l0) linger 116 depresses lbutton 98 and closes the circuit to the cylinder motor.

To secure proper alignment of the parts the set screw 113 lcan be loosened untilthe ykey 87 is `in the opposed .grooves lland 12d at which time collar 112 can be turned until linger 115 depresses button 93 until the switch is closed, whereupon vset screw 113 can be tightened.

Sufiicient clearance is provided between bushing 11i) and collar 112 to permit the necessary travel of bushing 11d, but when the key 87 drops into groove 12@ there will be little if any clearance between the sleeve 104 and the collar 112.

To stop the cylinder motor the handwheel is pushedV in, depressing plunger 1l@ until key 87 suiiiciently clears groove 12() to permit the key S7, to be radially rotated until it reaches slot 117 in collar 105, after which the wheel can be lifted out completely. The motor stopped, of course, as soon as linger 116 released button Q8. The handwheel is now available for use in unlocking the cylinder doors as hereinabove described.

FIGS. 7 and 8 show, in section, certain details not fully characterized hereinabove. The meeting plane of door parts and 26 is shown at P in each figure. The guide blocks 121 and 122 are carried on the respective door edges. FIG. 7 shows the upper door pivot point at the hinge pin 123. Strengthening

straps

124 and 125, respectively on the tub and the door and the cylinder, are shown in respective FIGS. 8 and 7, and in perspective in FIG. 2 and the horizontal strengthening strap 125 is also shown in FlG. 7 and FIG. 2.

While l have shown a washing arrangement in which two cylinders are operated end-to-end in a unitary set-up, a single-cylinder washer is of course usable for a less extensive operation. It would also be quite feasible to adapt a latching and clamping device, such as I have herein shown, to a bylinder having only a single door instead of the two-part door shown in the gures. Similarly, it

would be quite feasible to have a clamping means which clamps only one latch handle instead of a pair of latch handles simultaneously.

What is claimed is:

1. ln a latching and locking mechanism for a door movable between open and closed positions in a door' frame, said mechanism including a latch 4bolt movably mounted on said door, said frame having a retainer socket in alignment with the path of movement ,of said bolt so as to receive an end of said bolt in door-latching position, a vhandle carried on said door, means operatively connecting said handle and said bolt whereby, upon handle swing, said bolt is moved to latched or unlatched positions, clamping meanscarried on said door and movable to retain said handle when said handle is moved to doorlatched position, arotatable member also carried on said door, a togglelinkage, one end of said toggle linkage being connected to said rotatable member and the other end to said clamping means, and means for rotating said rotatable member whereby said toggle linkage is actuated, and saidclamping meansis moved to handle-clamping position.

2. Mechanism as defined in claim 1 wherein said clamping means consists of a clamping bar slidably mounted to permit movement to a position blocking operation of said handle when in door-latched position.

3. 1n a latchingand locking mechanism for a door movable between open and closed positions in a doorrame, said mechanism including a ,pair of latch bolts mounted kon jsaiddoor to move in opposite directions thereon, said frame having opposed sockets in respectively opposed frame portions, each socket being in alignment with the .path of movement of ,arespective bolt whereby to receive a respective end of the last said bolt in door-latching position, a `pair of handles carried on said door, means operatively connecting each said handle and its said bolt whereby, upon swing of said handle, its connected bolt is moved to latched or unlatched position, clamping means carried on said door and movable yto retain each said handle when said handle is moved to door-latched position, arotatable member, a toggle linkage, one end of said linkage being connectedto said rotatable member and the other end to` said clamping means, and means for rotating Isaid krotatable member whereby said toggle linkage means is actuated, and said clampingmeans is moved to handleclamping position.

4. Mechanism as defined in claim 3 wherein said clamping means is slidably mounted to permit movement to a position blocking operation of said handle when in doorlatched position.

5. Mechanism as dened in claim 1 wherein obstruction means is provided on said clamping means to permit swing of the handle to door-latching position only when said clamping means has been withdrawn to an unclamping position.

6. Mechanism as defined in claim 1 wherein said rotatable member has a key slot therein, and means for rotating said rotatable member including a manually portable key carrier having an elongated key tittable in said slot, and means on said rotatable member for retaining said key in said slot when the key carrier has been rotated to door-unlatched position.

7. Mechanism as dened in claim 6 and including ejector means for removing said key from said slot when the key carrier is rotated to door-latched position.

8. Mechanism as defined in claim '7 wherein said ejector means consists of a spring-impelled plunger biased to exert ejecting pressure against said key.

9. Latching and locking means for the door of a rotatable cylinder of a motor-operated washing machine, said means including a latch bolt movably mounted onsaid door, a frame for said door having a retainer socket in alignment with the path of movement of said bolt whereby to receive an end of said bolt when the bolt is moved to door-latching position, a handle carried on said door,

means operatively connecting said handle and said bolt, said handle being swingable to latch and unlatch the bolt, clamping means carried on said door and movable to retain said handle in its door-latched position, electric circuit means adapted, when closed, to energize the motor, a switch in said circuit and a key member removable from a first position to a second position spaced therefrom, and adapted when in said rst position, to canse clamping and unclamping of said latch handle and when in said second position to cause closing of said circuit only when said latch handle is in latching position.

l0. In a latching and locking mechanism for a door movable between open and closed positions in a door frame said mechanism including a pair of latch bolts mounted on said door to move in opposite directions thereon, said frame having opposed sockets in respectively opposed frame portions, each socket being in alignment with the path of movement of a respective bolt whereby to receive a respective end of the last said bolt in door-latching position, a pair of handles carried on said door, means operatively connecting each said handle and its said bolt whereby, upon swing of said handle, its connected bolt is moved to latched or unlatched position, clamping means carried on said door and movable to retain each said handle when said handle is moved to door-latched position, a rotatable member, a toggle linkage, one end ot said linkage being connected to said rotatable member and the other end to said clamping means, and means for rotating said rotatable member whereby said toggle linkage means is actuated, and said clamping means is moved to handle-clamping position, said rotatable member having a key slot therein, means for rotating said rotatable member including a removable key carrier having an elongated key receivable in said slot in a first position whereby by movement of said key carrier said rotatable member is actuated, electric circuit means adapted when closed to energize the motor, a switch in said circuit, receptacle means adjacent said switch to receive said key carrier in a second position spaced from said irst position, said key carrier when in said second position being movable to either one of two settings, and adapted, when in one setting, to permit opening of said circuit, and when in the other setting to cause closing of said circuit, said key carrier being removable from said iirst position only when said clamp is in clamping position.

11. Latching and locking mechanism for a door movable between open and closed position in a door frame including a latch bolt carried on said door and movable to a door-securing position and means for retaining said latch bolt in said door securing position including bolt clamping means carried on said door, a rotatable member also carried on said door and operatively eiective on said clamping means to move it to clamping position, a,

handwheel having a key portion ittable into an aperture in said rotatable member whereby, upon movement of said handwheel, to rotate said rotatable member, a locator member Xed on said door above said rotatable member and having a cut-away slot to admit the said key portion of said handwheel to operative engagement with said rotatable member when this member is in clamping position and to retain said handwheel when the rotatable member is rotated by the handwheel to unclamping position.

12. Mechanism as dened in claim 11 wherein said operative engagement between said rotatable member and said latch bolt is a toggle linkage connected at one end to said bolt and at the other end to said rotatable member.

13. Mechanism as defined in claim 11 wherein a plunger is movably mounted beneath said rotatable member, and spring biased to pass through said aperture and into said slot when the said aperture and said slot come to alignment in bolt clamping position, said plunger being depressible by said key portion of said handwheel when the handwheel and key portion are inserted to move said rotatable portion to unclamping position.

14. Mechanism as dened in claim 2 wherein said door has two parts swingable on respectively opposed hinges to a closed position in which the respective free-swinging edges are in edge abutment, a socket on each door part adapted to receive respectively opposed ends of said clamping bar when the clamping bar is moved to said handle-blocking position, whereby to provide door securing means additional to the clamping of said handle.

References Cited in the le of this patent UNITED STATES PATENTS 2,038,066 Strobridge Apr. 21, 1936 2,088,915 Manchester Aug. 3, 1937 2,140,621 Gerlach Dec. 20, 1938 2,228,408 Schwarz Ian. 14, 1941 2,659,782 Wolf Nov. 17, 1953

Claims

1. IN A LATCHING AND LOCKING MECHANISM FOR A DOOR MOVABLE BETWEEN OPEN AND CLOSED POSITIONS IN A DOOR FRAME, SAID MECHANISM INCLUDING A LATCH BOLT MOVABLY MOUNTED ON SAID DOOR, SAID FRAME HAVING A RETAINER SOCKET IN ALIGNMENT WITH THE PATH OF MOVEMENT OF SAID BOLT SO AS TO RECEIVE AN END OF SAID BOLT IN DOOR-LATCHING POSITION, A HANDLE CARRIED ON SAID DOOR, MEANS OPERATIVELY CONNECTING SAID HANDLE AND SAID BOLT WHEREBY, UPON HANDLE SWING, SAID BOLT IS MOVED TO LATCHED OR UNLATCHED POSITIONS, CLAMPING MEANS CARRIED ON SAID DOOR AND MOVABLE TO RETAIN SAID HANDLE WHEN SAID HANDLE IS MOVED TO DOORLATCHED POSITION, A ROTATABLE MEMBER ALSO CARRIED ON SAID DOOR, A TOGGLE LINKAGE, ONE END OF SAID TOGGLE LINKAGE BEING CONNECTED TO SAID ROTATABLE MEMBER AND THE OTHER END TO SAID CLAMPING MEANS, AND MEANS FOR ROTATING SAID ROTATABLE MEMBER WHEREBY SAID TOGGLE LINKAGE IS ACTUATED, AND SAID CLAMPING MEANS IS MOVED TO HANDLE-CLAMPING POSITION.