US 2422795 A
Description (OCR text may contain errors)
June 24, 1 947, J MQKNIGHT 2,422,795
Filed July 28, 1945 INVENTOR.
ZAU/TEA/CE I I7: KNIGHT A fforlrjv S Patented June 24, 1947 UNITED STATES PATENT OFFlCE LOCK Laurence J. McKnight, Lakewood, Ohio Application July 28, 1945, Serial No. 607,634 7 (01. 254 98) 11 Claims. 1
This invention relates to screw jacks and columns that are adjustable in length and adapted, among other uses, for shoring up floors and the like. More particularly it relates to means for locking such jacks or columns in an adjusted position so that their lengths cannot be altered unwittingly as by vibration of a building or inadvisedly as by tampering with the device.
Adjustable columns of the class to which this invention pertains are known in the art and are used, inter alia, to raise to their original or intended levels, walls, flooring and floor beams and the like of buildings that have sagged or become displaced from'their intended or desired level or condition. To prevent cracking of the plaster on the walls and like damage the actual raising is desirably done gradually over an extended period of time. For this reason columns are employed whose length may be varied by adjustment of two members threaded together. After such a column has been put'in position it may be gradually lengthened by rotating the parts relative to each other at odd fractioned turns at selected intervals, sometimes days apart, while exposed to vibration or other adverse influences and frequently exposed to'perso'ns who may be inclined to tamper with it. In either case its length may be undesirably altered with con sequent harm to the task at hand. Such columns may also be used to permanently and adjustably shore up floors where additional or changing loads such as added or altered ma-.
chinery are placed in buildings, and it is desired to increase the load on certain columns or reapportion the load between columns. In all events it is desirable that the columns be adjustable in length and securely locked in desired positions between adjustments. Similarly it is desirable that the columns be readily unlocked by a proper person for the sake of making proper and necessary adjustment to the lengths thereof. While my locking device is herein particularly illustrated and. described in the environment of an adjustable'column, my invention also has application to and advantages with many forms of screw jacks such as mining, shoring and other load bearing jacks. 7
Generally speaking the locking mechanism of my invention is so arranged-that when inlookll'lg position the column or jack length cannot be changed without camming the load over a cam surfaceof the lock that operates on a moment arm'thatr'equires greater than available effort to move. The locking mechanism preferably engages-the screw mechanism at the pointwhere umn.
bearing column or jack. A further object of the invention is to provide an adjustable column or jack with a locking means of the Vernier type to permit retention of the parts in any desired one of a multitude of adjusted positions. Still another object'of the invention is to provide a tamper-proof lock and one that resists in advertent movement with substantially the force of the load supported by the locked jack or col- An additional object of the invention is to provide a column or jack with a locking device that occupies a hole or bore by which the jack or column is engaged by the tool used to adjust its length. Another object of my invention is to provide a screw jack or column locking device that is simple and compact and that can be readily adapted to or incorporated with jacks or columns of conventional design. Another object of my invention is to provide a quickly removable and attachable lock for screw jacks and adjustable columns, the locking and unlocking of which can be readily and quickly eifected under proper and controlled circumstances.
Otherobjects of the invention will appear from the accompanying drawings and the specification. The novel features of the invention are summarized in the claims. In the annexed drawings, in which a preferred form of my invention is illustrated:
Figure l is an axial section through an adjustable column employing my invention; Figure 2 is a section taken along the lines 2-2 of Figure 1; Figure 3 is an exploded view of the column to better showthe component parts; and Figure 4 is a bottom plan view of the locking key shown in side elevation in Figure 3.
Referring now to the drawings I have illustrated a preferred forn of my invention in the environment. of an adjustable shoring column useful for raisin beams, floors, joists and the like in which the tubular column member [5 carries at its upper end a cap Ill which bears against the floor, or the beam of the floor, that is to be raised. To iacilitatethis engagement and prevent slippage between the parts the load engag- .lyingcat. :right. angles-to: :each other.
ing surface of the cap H] is provided with a series of intersecting grooves and projections H preferably of waffle-like configuration. The under side of the cap is recessed at [,4 to provide an inset seat for the end of the load supporting member l5. This inset seat insures that the cap and column will at all times be held in the desired position each to the other.
The column member l consists preferably of a length of steel pipe or tube-of wall thickness and overall diameter suflicient to sustain the load for which the column is intended. This member is cut oil square at each end and its... upper end is received in the recess M of the.
A hollow internally threadedunutflzll engageszi the other end of the column. member. l5 and isformed, as shown in the drawing, with a slightly tapered portion H! for insertion into :thelower end of the column member. At its maximum diameterthe taper preferably providesfor a snug fit.- with the internal surface of the column; memtype: to-receive' :a -.correspondingly threaded jack screw 25.
Relative rotation between :the nut I1 and :the screw .2 E-changes-the overallzlengthof .the entire column :st-ructure. To this end: the threaded shank ofthescrew --25 is .of'sufiicient length to permit the desiredadjustmentinthe length of the whole 50011111111 structure; screwedinto the nut l1 its upper endfis received insidethe member I 5, 'whence'itis withdrawn by reverse 'action inithe-nut; 11 to extend the length of-the column;
.To make engagement witha .base'plate as hereafter described the lower end of-the screw 25 'iseformed with a smooth, approximately semisp-herical headfZ'k Therend surface of this head is :convexinshape; andisadapted to be received in-a= complementary smooth concavity 28 of slightly klargeriradius formed in thebase plate :30; The-coactionbetween the surfaces 2! and 28 insure :thatnthe screw 25 and the plate-30 will centerandalign themselves with respect to each other when .the column is adjust-ed to take -a load, and byrvirtue ofnthe small difierence'in radii will have small: frictionunder loads Above the bearing surface. 22 the-head orthescrew is pierced by; intersecting transverse :holes :58, preferably The holes eachserveth'e dual purpose :of receiving ;a turninggbarrfor rotating the screw under load and alternatively and respectively receiving a part of the locking mechanism as will: more. .fully appear below.
From the vdescriptionithuswfar it will be seen that 12311001 or other load-t may bezliftedby placing the cpl-ate 3H on -.a:- suitable foundation and thereafter :rotating :the screws; 25 in the :nut I 1 until the soap vi 6 engages and. assumesthe .--load. As this lifting action takes placethere isrelative rotation .not ionlyibetween theinut; and screw: but also rbetweeni the surfaces:21 and-28.0f- -the screw and'baseplate' r fill The :shape :of the surfaces '21 andi28:facilitatesnthis rotation: although if desireda lubricantmay'becadded to increase the ease'swithnwhich the partsiare turned and the column length-is adjusted.
After the :column has been adjusted to take an initially; desired :load, it is frequently: necessary Asthe shank. is
4 to wait a considerable period of time before the load is lifted further. This may well be the case to prevent cracking of the plaster on the walls or other harm to the building that is liable to occur if it be raised too abruptly. Accordingly it is advantageous to be able to rotate the screw 21 a fraction of a complete revolution at stated intervals, sometimes days apart. Such a mode of operation means that the column must support the load above it for long iorshort periods of time during which it is quite undesirable that there be either inadvertent or wrongful change in length of the column. It is therefore desirable that the column be securely locked when ad- "iusted and readily unlocked for adjustment.
such columns may bear their loads as from time to time adjusted .for many years during which the hazards of misadjustment or maladjustment persist;
The present invention is directed to the lock .mechanism .to insure retention: ,ofv the parts i of theicolumninr-anl adjusted. position. for :as long a periodmasisrdesired. Such'a lock iseffected by preventing relative rotation between .the screw '25 and the :base 3fl.. 'It. has .been. found that looking .these members sufiicient to-loclnthe -.entire column .in. adjusted .-.position. Under 1 loadwthe frictional engagement between! the -memben I 5, the cap-1.19 .andthe floorlbeamsxaboue isz so great thatttheir relative rotation is. s practically impossible... -similar-l-y .-the.; column load acting through! .the-relativelyslarge radius bearing areas betweenthemember.|5.and thenut: H and between-lthe-v base plates, 30 andsthe qfloor 1 inhibits turning, therebetween forrall ,practicable purposes.. As -a consequencecazlook between 2 the screw :25 .and the plate '38 =actseffectively to lock the screw -25.and the nut J1 with-respect to each other. Thelimiting bearing -.areas between the screw and the anutpand "between; the surfaces 21 and 28 li-mittall practicable-movementunder. load to relativemovement betweenthe screw -and the nut and the-base'whereby holding-the screw relative .toithe base 'servestoloek the-column as well as .it the screw werelocked directly -tothe nut.
Tot-effect. the docking gaction. described above a plurality :01;v recesses i5 :-(three as I prefer and have shown") arexiormed :in the upper surface of the plate 3fl. -.-Each' ofcthese-srecessespreferably .has afiat-bottom :portion ;36-.par.alle1 with the under side of .theplate..39 and .a side wall: 38 normal-tone. column radiusethat intersects it at its amidepoint. On leach-side breach .-reeess are radially -disposed. :side walls -39 perpendicular to :the surfaoesz3fis.
A lockingw-lugellli, iormed withwasshank- 48 and attransversely extending head 42; is :used .toengageeaselectedmecess :35--of., theplate 30. The actuareneagement with the recess is eifected by the \head- 43 2 whose ewidth and shap cor-responds tothe shapeof .the recess .-35 w-hereby-to besnugly -xengageable therewith. A ifiat-surfacerdt' on the rbottom; ofethe 21188111255 adapted to. lie closely adjacent toetheeiuxtaposed surface 36 on the plate 30.1 .Ateaclr side ofithe head is an-angulare ly-disposed sidewall .46 =ad8ptedrtohave wedging engagement with the inclinedsideiwalls 3970f the .-reeess:;35':as .-theshead-;of the-lug All .isinoved radially inwardofrtherecess In =-this position the shankvi l8 of :the lug dflcwill lie eacross the axis of the screw Z5KlII-0ll80f-17118 11018559; When the -lug, 40 is positioned. and secured with. its head 42 .in, engagement with, airec-ess 35 and its 1 shank 4fl iextendingcthrough.ua hole Jill it\wi1l be-seen that; th screw: anda base'jplam are effectively locked against relative rotation. If any relative rotation between these parts is attempted the head 42 will necessarily have to rotate about the axis of the shank 48 and tend to cam about an edge of the face 44. This would require raising the entire load supported by the column, and thus insures that the load enters into the looking effect. I
To look the member 40 in position in a bore- 50 the shank 48 is threaded as at 52 to receive a nut 54. A hole 55 is preferably provided in the end of the shank 48 to receive a padlock P shown I in Fig. 1 to prevent removal of the locking member from an effective locking position by an unauthorized person.
At the time it is desired to change the length of the column, the lug 40 is removed and a tool or bar affording sufficient leverage is inserted in a hole 50 to turn the screw in the nut I'I. Since the frictional load on the nut prevents its rotation in the member I5, the screw turns in the nut to change the overall length of the column. When the desired change has been made the lug 40 may be replaced and secured and/or padlocked in position.
It has been stated above that frequently it is desirable to adjust the column length by small increments through rotation of the screw only part of a revolution. For this reason provision has been made for locking the screw 25 in any one of a multitude of positions with respect to the plate 30. To permit this a vernier effect is provided. This is obtained in the present construction by having three equi-angularly spaced recesses 35 in the plate and four effective positions for the member 4'!) in the two shank receiving holes 50 in the head of the screw 25. This latter relation is true because the shank may be inserted into any hole 50' of the screw from either side thereof. Thus the head 62 of the lock 40 may have any one of four locking positions 90 apart relative to the screw for coaction with any of the recesses which are spaced 120 apart. The head 42 may therefore find a recess for locking engagement every 30 of rotation of the screw relative to the plate.
While I have illustrated and described a preferred form of my invention in the environment of one advantageous use, modifications, improvements and changes as well as other uses and environments will occur to those skilled in the art upon their understanding of the precepts and examples hereof, and I do not care to be limited to the specific forms and disclosures hereof nor in any manner other than by the claims appended hereto.
1. The combination of a load bearing part having an end adapted to be rotatably supported, a non-rotatable bearing member rotatably supporting said end, said member having a plurality of recesses adjacent said end, said end having a plurality of holes extending transversely thereof, a locking lug having a head and shank adapted to be removably positioned with its head in one of said recesses and its shank in one of said holes to lock said part and said member against relative rotation.
2. The combination of claim 1 in which the head of said lug has a corner engageable in said recess tending to move said end out of engagement with said member before. permitting rotation therebetween.
3. The combination of claim 1 in which the sides of the head of said lug and the juxtaposed walls of said recess'similarly converge toward'the axis of said parts whereby to give a wedged engagement between'said head and recess as the former is moved toward the axis of said parts.
'4. Thecombination of claim 1v with means for locking said shank in one of said holes.
' 5. The combination of claim 1 in which said shank is threaded and cross drilled, with a nut threaded on said shank and engaging said end, and a padlock removably secured in said cross drill.
6. The combination of claim 1 in which the number of said recesses differs from the number of positions the head of said lug may assume relative to said end when said shank is in one of said holes.
7. The combination of claim 1 in which said holes are two in number and intersect at right angles in said end and said member has three recesses equi-angularly spaced about the axis of said end.
8. A support that is adjustable in length comprising a load bearing member and a screw in threaded engagement therewith and having an axially aligned free end, a base member providing a bearing for the free end of the screw and rotatably supporting said screw, a plurality of locking recesses formed in the top surface of said base, a plurality of holes extending through said screw and lying in the same radial plane of said screw, a removable locking member having a head and a shank adapted to be positioned with its head in a recess and its shank passing through one of said holes to lock said screw and base against relative rotation, and a locking element to engage said member and lock it in said screw.
9. A support that is adjustable in length comprising a column and a screw having an end in axial alignment with the latter and threadingly carried in the former, a base member providing a rotatable bearing support for the end of the screw, a plurality of locking recesses formed in said base, a plurality of locking recesses, different in number by one from the number formed in said base, formed in said screw, and a locking member to engage selectively with a vernier type adjustment a recess in said base and one in said screw to prevent relative rotation between said base and screw.
10. A support that is adjustable in length comprising a column and a screw with an exposed load bearing end in axial alignment with the latter threadingly carried in the former, a base member providing a bearing for the end of the screw and having an odd number of locking recesses, a lug having a head adapted to have positive and selective engagement with any one of said recesses and having a shank, the end of said screw having an even number of holes for receiving the shank of said lug while the said head enters one of said recesses.
11. An adjustable and. lockable load bearing support of the class described comprising a tubular column member, a cap member with an external load engaging surface having inward load bearing contact with one end of the column, an internally threaded nut adapted to have load bearing engagement with the other end of said column, a base member with an external load engaging surface and a concave anti-friction bearing surface facting toward said nut, a screw with a smooth convex head adapted to fit into said concave bearing surface and having a threaded shaft fitting the internal thread of said nut, a bore in the head of said screw nor- 7 8 maleto .thezaaxis thereof, a; recess 12 in :.said :base member; and ai-lockingxmemberito" engage said REFERENCES "CITED bore 'and'said recessioselctively lock saidzscrew and-said base: against rotation relativento' each Thejonowmg references mmofwrecord other; said externaixload engagingzsurfaces .in- 5 file of'this Patent:
hibiting Amovementbetween said: capand-base H members and the externalwloadfand said cap UNITED STATES PATENTS and nut frictionally engagingythewendsSof-rsaid lumn on surfaces f reater radii than-the Number Name Date :Zdiusbfthe bearing are abetween the head f 1379371' Toscas May 1921 10 1,891,588 Claus Dec;20;11932 said screw and said base member. LAURENCE -.J.' McKNIGI-IT;