US1298316A - Screw-jack. - Google Patents

Description

VH. L. EWING.

SCREW JACK.

APPLICATION FILED MAY 2. |918. 1,298,316. Patented Mar. 25,1919.

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SCREW JACK.

APPucATloN man MAY 2. 19m.

Patented Mar. 25, 1919.

2 SHEETS-SHEET 2.

HARRY L. EWING, OF DALLAS, TEXAS.

SCREW-J ACK.

Application led May 2, 1918.

To all whom it may concer/n.'

Be it known that I, HARRY L. EwING, a citizen of the United States, residing at Dallas, in the county of Dallas and State of Texas, have invented certain new and useful Improvements in Screw-Jacks, of which the following is a specification.

This invention relates to jack screws and tools of like type, and has for its object to provide a tool of this character with a simple, strong and eiicient means for raising and lowering the screw by an operating handle movable transversely of the axis of the screw and adapted to actuate the screw when the tool is placed in more or less inaccessible positions such as below a building, in a corner or close to a wall. Between the screw and handle are placed oppositely engaging pawl and ratchet devices by which the screw is turned when the swing of the handle is limited and so insure extension or retraction of the screw.

A further object of the invention is to provide within the base of the jack screw an alarm mechanism, preferably of an audible character which will automatically indicate to those using the jack screw when the screw has reached the safe limit of extension and thus prevent the danger of projecting the screw to an unsafe distance whereby it becomes disengaged from the base and is liable to fall and so endanger the lives of the persons within the vicinity through the possibility of the object that is being raised,

Vfalling when the screw becomes released.

With these objects in view, together with others which will appear as the description proceeds, the invention resides in the novel formation, combination, and arrangement of parts, all as will be described more fully, hereinafter, particularly pointed out in the claims, and illustrated in the accompanying drawings, in which,

Figure 1 is a side elevation of the jack screw complete.

Fig. 2 is a central vertical sectional view of the same.

Fig. 3 is a horizontal sectional view through the head of the jack screw on the line 3--3 of Fig. 2.

' Fig. 4 is a cross sectional view of the head on the line 4.-4 of Fig. 3.

Fig. 5 is a similar view on the line 5-5 of the same figure.

Fig. 6 is a horizontal sectional view of the Specification of Letters Patent.

Patented Mar. 25, 1919.

serial NQ. 232,107.

base on the line 6-6 of Fig. 2, the coupling screw being shown in its elevated position.

Fig. 7 is an elevation partly in section of the audible alarm device used with this invention. A

Fig. 8 is a horizontal sectional view on the line 8 8 of Fig. 2, and,

Fig. 9 is a vertical sectional view of the lower end of the operating screw.

In the drawings, 12 indicates the base of the tool made as usual with an expanded foot and an upwardly inwardly tapering body provided at one side with a grip or handle 13 by means of which the tool may be transported from place to place and adjusted in position below an object to be moved. Through the top or smaller end of the base is formed a threaded opening extending longitudinally thereof in the axial line to receive the actuating screw 15 which passes downwardly into the body when the jack is in its lower position. At the extreme end of the top 14 is a cylindrical projection 16, shouldered where it joins the base to form a support and bearing for a laterally swinging head 17 when in its lowest position, said head serving to rotate the screw 15 so that it maybe projected and retracted.

The screw 15 at its upper end is provided with a ratchet disk 18 having peripheral V-shaped teeth as shown in Fig. 3, said ratchet being rotatable within the head 17 between a flange 19 in said head and the top of the base. A'bove the ratchet 18 is a slightly reduced `cylindrical bearing 20 around which the flange 19 turns. Extending upwardly from the bearing 20 is a square projection 21 over which is placed a second ratchet disk 22 of similar shape to the ratchet disk 18. Preferably the ratchet disk 18, bearing 2O and projection 21 are integrally formed with the screw.15, while an integral stem 23 projects from the part 21 and has a screw thread formed on its outer end. The head 17 is rotatable or adapted to swing upon the bearing 20, being supported by the annular flange 19 resting upon the top of the ratchet disk 18so that when the screw is rotated to move it longitudinally, the head 17 will move with it.

The ratchet disk 22 bears upon the top of the flange 19 and is held thereon by an anti-friction bearing 24: placed between the upper surface of the ratchet disk 22 and the under-surface of a bearing cap 25 that is placed against the object to be lifted. The cap is held in placeV upon the stem 23 and against the anti-friction bearing 24Y by a nut 26 threaded on the outer end of theV stem.

the base 12 and in each side of the head are formed two horizontal notches 27 and 28 Y is a pawl .33 formed with two fingers 34 and 35 seated in said notches and pivotally heldY 'therein by .a vertical pin 36, said fingers each` having a toe 37 adapted to Vengage one of the vratchet disks to turn'the screw 15 in onedirection. The tail of-the pawl is made with a vertically curved shoulder 39 fora purposesoonto be' described. A coil spring 40 between the wall 31 and the Y tail of the pawl 33 tends to maintain the toes Y Near its outer end, the head 17 is of cir- `cular cross section, as shown at 41 Fig. 5, to

of the pawls in engagementwith the teeth .of the ratchet disks. On the opposite side of Vthe head 17 is a similar pawl 33a, the fingers of whichunder certain conditions, engage the ratchet disks and reverse the movement of the screw.

providea bearing for a camvring 42 which encircles the tails of the pawls 33 and 33a Y 4ring 42. By thismeans the operator will atL all; times be aware of the condition lof his Vtool and know which of the pawls 33,33a are and by means of which ring the pawls are disengaged from the ratchet disks. This 4rlng has an eccentric or cam portion 43 on its inner circular face at a greater distance from the axis of rotation of the ring than the' remainder of said inner face Vby ywhich means when thecam portion 43 alinesor is brought` opposite Vone of the pawlsf, the

spring 40 presses the tail of said pawl outwardly into this cam portion'and causes the toes on thengers to enagage the teeth of the ratchet disks. 'A half turn ofthering will'rcarry the cam surfacethereof to the' opposite side and `permit thepawl onY said side to engage the ratchet disks.` This movement of the ring brings the concentric Vsurface of its inner face into engagement with the 'curved shoulder 39 on the tail of the pawl previously in engagement with thel ratchet ,disk and causes said pawl to become disengaged. VMeans are Vprovided to` limit the movement of the ring 42 to a semi-rota-Y tion, saidmeans comprising a pin 65 projecting radially from the head 17 into Va semi-circular slot on the outer side of the One end of the headil7 projects beyond in engagement. A Thei'extreme Z end ofthe head 17 is" threaded at 44 to. receive aV threaded retaining ring 45 for holdingtheV Y cam ring A42 in place. y

In connection with this tool is anY alarm,

preferably, audible, which is'operated by the screw when in its highest or Vmost extended position, compatible to safety, and comprises alongitudinal Yshaft 46 carried inbearings 47 and 48 bolted or screwed against the wall of the base 12 within a cavity 49 formedtherein. At the upper end ofl thejshaft is affixed a latch 50 that extends crosswise of Y the shaft and adapted to berengaged by ap pawl 51 pivoted in a groove 52 formed .in

thebottom of the screwl, the pawl' pro jecting a short distance beyondwthe side of Vthe screw so asto engage the trigger .50 and rock the shaft 46. Acoil springv 53 is suitably fitted Vto the pawlV 51y for'the purpose of normally maintainingA it in a horizontal position with its end projecting beyond the 5 screw, but which will swing downwardly! and out of the way when Vthe screw is to beV entirely removed Vfrom the base.

54 extending outwardly from said shaft and is provided on its free'end-withV a hammer.

55 to strike a bell 56 andY give an alarm The arm 54 is retracted or moved away from the Near the. lower end of the shaft 46 issecuredan Aarm bell when the trigger isrocked by the pawl Y 51 and moved toward the belljtocause the.

hammer to strike, by Va spring V57 coiled around the shaft 46 above the bearing 48 and secured at one end to thebearing, its opposite end being attached to afcollar 58 threaded on the shaft and provided with a screw 59 for holding said collar against movement after the spring has been'properly' Y Y N Y Y f v105 In addition to thebell 56 .whichisof the.VV gong type there is also employed `asecond-1 adjusted.

bell 60 of a continuously Yringing or lj-in, ling type which is mounted on'theV lower end of an arm 61 pivotedat 62to the base 15 and having a free upwardly V extending end that is embraced by a fork631o1'iythee'nd'of the hammer arm 54, the arrangement beingjsuohi Y that when the shaftr46. is moved away from the bell 56, the bell 60 will ring throughithe action of the fork 63 on V.thev arm 61,andon the return or striking movement of. the arm 54, the bell 60 will also ring.

The operation of the tool is self evident.l`

Then in position, a semi-rotation'of the *cam 120 means 42 will disengage oneofthe' pa'wis 33, 33a from the ratchet disks and permit'V l the other pawl Vnndertension of its spring v40 Y to engage said disks and upon movement 0f the head 17 the screw 15 will beturned ini one direction; if however, the ring 42i'be given a semi-rotation in the opposite'direc tion, the pawls heretoforefreeofthe ratchet disks will be engaged therewith and the opi pos'ite pawl released. In this position moveisoV ment of the head 17 turns the screw in the opposite direction. The screw rotated in one direction or the other as described will cause it to be projected from or retracted into the base 12 in well known manner.

When the screw 15 has been projected from t'he base 12 as far as it is safe for it to go, the pawl 51 on the lower end of the screw will engage lthe trigger or latch 50 and rock the shaft 116, thereby swinging the arm 54 and the hammer 55 away from bell 56 which as soon as the pawl 51 passes the latch are forcibly returned to normal position by the spring 57 and the hammer caused to strike the bell 56, giving a signal that may be audible at some distance from the pack. In addition to the alarm from bell 56 the jingling bell 60 is also caused to ring by the fork 63 rocking the arm 61, to which the bell is attached. The alarm will be operated several times if the screw continues to be rotated, so should the first signal be unheeded the second or third will be sufficient warning.

The foregoing description and the drawings have reference to what may be considered the preferred, or approved form of my invention. It is to be understood that I may make such changes in construction and arrangement and combination of parts, materials dimensions, et cetera, as may prove expedient and fall within the scope of the appended claims.

Havin thus fully described my invention, what I c aim as new and desire to secure by Letters Patent, is:

1. In a tool of the kind described, the combination of a base, a screw longitudinally threaded into said base, a pawl on the lower end of said screw projecting laterally from the side thereof, a vertical shaft within said base at one side of said screw, a lug on the upper end of said shaft adapted to be engaged by the pawl on said screw when raised to its highest osition for rockino' said shaft, an audible a arm within said base, and a hammer on the lower end of said shaft for striking said alarm when said shaft is rocked.

2. In a tool of the kind described, the combination of a base, a screw longitudinally threaded into said base, a pawl on the lower end of said screw projecting laterally beyond the side thereof, a vertical shaft journaled within said base substantially parallel to said screw and at one side thereof, a lug on the upper end of said shaft in position to be engaged by the pawl on the screw when the latter is raised to its highest position and rock said sha-ft, an audible alarm secured within said base, a hammer carried by the lower end of said shaft for striking said alarm when the shaft is rocked, a second alarm within the base carried by a pivot arm for actuating said alarm, and a finger on the aforesaid hammer for striking said arm when the hammer is operated.

In testimony whereof I afix my signature in presence of two witnesses.

HARRY L. EWING. Witnesses S. C. FOOTER, JN0. CLARK.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. G.

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