US455995A - Lifting-jack - Google Patents

Description

(No Model.)

5 J. BARRETT.

LIPTING JACK.

Patented July 14, 1891.

UNITED STATES PATENT U FICE.

JOSIAH BARRETT, OF ALLEGHENY, ASSIGNOR TO THE DUFF MANUFAC- TURING COMPANY, OF PITTSBURG, PENNSYLVANIA.

LlFTlNG-JACK.

SPECIFICATION forming part of Letters Patent No. 455,995, dated July 14, 1891. Application filed April 30, 1891. Serial No. 391,067. (No model.)

To all whom it may concern: ment with the toothed bar. In the said ap- Be it known that I, JOSIAH BARRETT, a plication, filed February 13, 1891, the said resident of Allegheny, in the county of Alleaction is obtained by means of rigid pins or gheny and State of Pennsylvania, have infingers on the pawl engaging with a shoul- 55 vented a new and useful Improvement in dered tripping-plate, which is yielding, and Lifting-Jacks; and I do hereby declare the so yields when one of said fingers comes in following to be afnll, clear, and exact descripcontact therewith, but, as soon as the pawl is tion thereof. free from the pressure of such yielding trip- My invention relates to what might genping-plate, draws the pawl from engagement 6o 10 erally be termed jacks that is, to power with the toothed bar.

mechanismin whichastep-by-step movement The object of the present invention is to back and forth is obtained, said mechanism improve these classes of jacks in certain parbeing actively operative in one direction to ticulars, especially as to the power employed move or raise a load, and being passively opfor lifting the upper or outer pawl and as to' r 5 erative in the other direction to control the the construction of handle to be employed movements of theload, such as loweringaload with the jack. lifted by the jack. By such terms it is of The main point of the invention desired to course to be understood that the invention be covered consists, generally stated, in the includes any device embodying this principle, combination, with the bar having teeth on 20 whether the power is exerted in a vertical, one face thereof, of the operating-lever, of horizontal, or other line. two pawls pivoted thereto and engaging the My invention relates more particularly to toothed bar, and a tripping-lever carried by that class of lifting-jacks describedin Letters the outer pawl and having one end bearing Patent No. 312,316, granted to me February on a pin or finger of the inner pawl, while 25 17, 1885, and in application filed by me Febthe other end bears against a shoulder, so ruary 13, 1891, Serial No. 381,275, in which that when the inner pawl is raised and the jacks the operating-lever carries two pawls, outer pawl lowered the upward movement of one on each side of the fulcrum-point, both the inner pawl and downward movement of of which are adapted to engage with a bar the outer pawl and the lever carried thereby 8o 0 having a toothed face on one side only, so as will, through such lever, cause an outward to impart a movement to the movable part of movement of the outer pawl, and so free it the jack on both the upward and downward from the toothed bar. or forward and backward movements of the The other points of the invention will be operating-lever, and both said jacks providhereinafter more particularly set forth and 5 ing for the reverse movements of the parts claimed.

by mechanism which raises one pawl from To enable others skilled in the art to make engagement from the bar while the other and use my invention, I will describe the pawl engages therewith and permits the retrosame more fully, referring to the accompanygrade m0vement, the pawl free from the bar ing drawings, in which- 40 passing one tooth thereon and taking into Figure 1 is aside view, partly broken away, thenext tooth, so that the load may be lowshowing the operative parts of one form of ered or the movement of the load be conthe jacks; and Fig. 2 is a like view of the trolled after the power has been applied modification. Fig. 3 is a perspective view of thereto to raise or move the load, as mayhave the lower end of the operating-lever as cast. 5 45 been desired. In such Patent No. 312,216 Fig. 4 is a like view of the lever as finished, this operation is obtained by spring-actuated and Fig. 5 is a sectional View through such levers pivoted to the pawls and engaging lever. T with a stationary shoulder or shoulders Like letters of reference indica elike parts adapted to compress the spring, and as soon in each.- 50 as the pawls are free through such spring- The jack has the body or frame a, and the actuated levers draw the pawls from engage bar I) has teeth I) on one face thereof the con the bearing ct for the reception of the innerend of the operating orhand lever C, and pivoted to said operating-lever are the two pawls d e, which engage with the teeth of the bar b on the one face thereof, and which act to raise or lower the load, according tothe movement of the hand-lever, the inner pawl e being pivoted forward of the fulcrum-pin c, and hence being adapted to engage withand raise the toothed bar when the hand-lever is lowered, and the outer pawl d being pivoted back of the fulcrum-pin c, and being of greater length than the pawl 6, so that it engages with the toothed barabove thesame and is bar when the hand-lever C is raised.

In the construction of these jacks two points are found desirable: First, that the mass ofthe lifting action shall beobtainedwhen the hand-lever is pressed down-that is, through the operation of the inner pawlas more power can be exerted by the operator in the downward or pushing stroke than in the upward or lifting stroke of the hand-lever, and, secondly, that the pawls shall operate as nearly in a line with the toothed bar as practicable, the latter point making the raising of the load easier on account of the more direct action of the pawls upon the toothed bar.

It has not been found practicable, however,

to so arrange the pawls, especially for a jack, which operates vertically, as the pawls would not be so liable to take into the toothed bar, and for this reason it has been found necessary either to pivot the inner pawl, so as to give to it a considerable inclination toward the teeth and not have quite so great lifting power, or to provide the pawl with a counter weight or spring. It was also necessaryto pivot the outer pawl further out from the toothed bar,-so as to get a longer stroke to compensate for the loss of stroke in the inner pawl. By the present invention I find that I am enabled to get a sufficiently long stroke of the inner pawl to relieve the outer pawl of the necessity of so great a stroke, as I provide means for forcing inwardly the inner pawl, and that at the same time I can pivot the outer pawl nearer to the toothed bar, so getting a more direct action thereof,-

and reducing its stroke so that the operation of lifting the hand-lever is not so severe as in the ordinary jack. These advantages I obtain on account of the improvements form-' ing the subject-matter of the present application, and I have illustrated the pawls as pivoted in such positions as to obtain the results above stated.

In Fig. 1 I have illustrated the invention as applied to such a jack as forms the subjectmatter of the above-mentioned application, filed February 13, 1891. Tl1e inner pawl carries thereon a finger or projection f, which engages with the yielding tripping-plate g, said tripping-plate having a shoulder g with which said finger engages, the finger preferably extending down, so that the necessity of carrying the tripping-plate higher up to engage with the finger is overcome, while the power for withdrawing the pawl is exerted at the proper point. The tripping-plate has also the shoulder 9 which engages with the tripping-lever h, which is shown as pivoted direct to the outer pawl d. This lever h, has one arm h thereof, whichextends at a .for-

ward and upward inclination over to the pawl e, and engages with the shoulder or projection on said pawl, such as the shoulder f of said fingerf, or aseparate shoulder on said pawle,while the lower arm h of the tripping-lever extends down into the course of the tripping-plate adapted to engage with and raise the toothed g In the construction shown in said Fig. 1

' the tripping-plate g slid es in guideways onthe frame, the plate having the horizontal slots 1 t' therein, through which bolts t" t" pass, said plate being cut out, as at 9 to pass around the bearing a, and having also the arm 0, with which the cam r engages to press back i the tripping-plate.

On said tripping-plate is a pin 7c,extending outparallel with'the movement of the plate, and in line with this pin is a seat into which the pin 70 enters and within which is inclosed the spring k, which, by pressing out the pin, operates the sliding tripping-plate, so that the tripping-plate may yield when necess'ary,'said spring being compressed, and as soon as the parts are free the spring forcing the tripping-plate back to its normal position, and so imparting the necessary motion of the pawls to withdraw them from engagement with the toothed bar. In the case of the inner pawl e the fingerf, engaging with the shoulder g', will force back the tripping-plate until the pawl is free to be withdrawn, when said tripping-plate will direct contact of a finger -thereon with the tripping-plate. During the lowering operation, therefore, as the inner pawl e is raised it will force up the tripping-lever h, its shoul- ,der f traveling along the lower inclined face It is found that this operates.

of the arm h thereof, which extendsover and' bears on top of the shoulder f, while the lower arm 71 of the lever will bear upon the yielding tripping-plate g and compress the 'spring k until the outer pawl is free to be withdrawn, when as theinner pawl is raised and the outer pawl is lowered the downward -inovement of the tripping-lever, which bears upon the inner pawl, combined with the upward movement of the inner pawl and the carry it free from the toothed bar and hold it in that position until the tripping-lever g is freed from contact with the tripping-plate, so that the pawl may again engage with the toothed bar. During this operation it Willbe seen that the tripping-lever h is always bearing upon the inner pawl, and that itis through the pressure upon such inner pawl and upon the tripping-plate that the necessary force to withdraw the outer pawl is obtained. The resultof this is that said tripping-lever acts I to force inwardly the inner pawl and to cause it to engage with the toothed bar as soon as it is freed from the tripping-plate, and consequently even in a vertically-operating jack the inner pawl may be drawn more into line with the toothed bar without employing counter-weights, as above described. In the lift ing operation the tripping-lever always bears upon the inner pawl, and to insure its being forced into engagement with the toothed bar the upper arm of this tripping-lever may be weighted, as shown at h In Fig. 2 I have illustrated my invention as applied to the construction of jacks such as shown in said Patent No. 312,316, in which Fig. 2 each pawl D E carries a spring-actuated lever m Z, respectively, the lever Z on the inner pawl being pivoted at f and being substantially of the same construction as described in said patent, and the tripping-plate Gbeing illustrated as pivoted at g to the jack-frame and being positively controlled, so as to be held rigidlyeitherin the position to act with the mechanism to withdraw the pawls or drawn free from such mechanism by means of the cam or eccentric g, pivoted to the jackframe. In order to obtain the advantages of the present invention in this construction of jack I mount the spring-actuated lever m on the outer pawl at the point W, said lever having the arm m extendin down be-' low such pivotal point, and I have pivoted the tripping-lever H to the lower end of such spring-actuated lever m, its upwardly and inwardly inclined arm 11 extending over and bearing on the top of a shoulder formed on the pivotal pin f of the spring-actuated lever Z, while its lower arm H is adapted to engage with the shoulder g of the tripping-plate. The springs for actuating the levers m Z are wound around their pivot-pins and adapted to engage both with the levers and the pawls, as illustrated in the dotted lines. In such construction of jack the tripping-plate is held rigidly either in the position which permits the raising operation or in the position which causes the pawls to act to lower the load. As the inner pawl is lowered, its'spring-actuated lever Z comes in contact with the shoulder g of the tripping-plate, and said lever is thereby moved, so that it compresses its spring 19, and as soon as the outer pawl D takes the load the compression of this spring, while the lower end of the lever is bearing on the shoul der 9' otthe gipping-plate, will act to withdraw the pawl". On the reverse movement of the operating-lever the shoulder f on the inner pawl-ingrising will contact with and travel along the arm H of the tripping-lever H,

while the lower arm H of said leverbears 7 against the shoulder g of the tripping-plate G which is held rigidly, and the necessary result is that the lower arm of the lever m is pushed outwardly, so compressing the spring q between said lever and the pawl D, such compressing action continuing until the pawl d is lowered free from the toothed bar, when the combined operation of the upward movement of the innerpawlE, the downward movement of the outer pawl D, and the action of the spring to force the lower end of the lever on inwardly will, when the lower end of the lever H is held rigid, impart the necessary outward movement to the pawl D and draw it free from the toothed bar.

It is exceedingly desirable, and, indeed, praeticallynecessary, that the pawls mounted in the hand-lever shall be strongly supported by a seat which extends for the entire length of the base of the pawl, so as to sustain the exceedingly heavy strain brought upon this part of the jack. For this purpose a special construction is described in my said- Patent No. 312,316. That construction, while giving all the necessary strength, has the objection that it requires considerable machine-work for the formation of the side plates and other parts, and that it requires the removal of at least one such side plate to replace a pawl in case of a breaking of the same' To provide a strong mounting of each pawl within the hand-lever I have devised the construction illustrated in Figs. 3, 4, and 5, the.

c, while extending above the same in the form indicated are the flanges 8's, and in order to form a seat for a pawl I bore through such flanges and the body of the metal between them, as indicated at 8 so forming a true seat extending through said flanges and between the same. In order to supportthe boring-tool during this operation Igenerally form the casting with a slightly greater thickness of metal than thatremoved by the boring-operation, and after the boring out of such seat I cut or mill away the thin film or web 8 so left, so forminga perfect seat 10 for the reception of the pivot -pin t, which is formed at the base of the pawl.

In order to introduce that pivot-pin into its seat I cut through one flange-such as the flange s at the forward end th'ereofa slot o, sufticient to permit the introduction of the pawl, and said pawl can then be passed through the slot 1) into its seat to, formed in cured within the jack-frame its body will fit between said flanges sand 8 and will be heldj in place thereby. By such construction I'do away with the necessity of separate sideplates, forming the handle of an integral'c'ast-1 ing, which is much stronger. At the same' time I so mount the pawl in 'the hand-leverj that it may be quickly removed from the handle upon the withdrawal of the hand-lever? from the jack-frame; but is firmly secured. therein when the hand-lever is mounted within the jacloframe, while a perfect turned hearing or seat for each pawl is formed in the hand-leven'and an exceedingly strongand firm connection between the two is obtained.

By the particular improvementsin theoperative parts of the jack above described, I am enabled to obtain a long lifting-stroke when the operating-lever is lowered, and at shorter and easier lifting-stroke when the'opcrating-lever is raised,'so reducing'thelpower necessary to operate the jack, while at the: same time I am enabled further to reduce the power by bringing the pawls into more direct line with the toothed lifting-bar, and also to eX- ert sufficient power under such circumstances to raise the outer pawl free fromthe toothed bar in lowering the jack,'so greatly increasing its efficiency and ease of action. I

As above referred to, in the term jack I include any mechanism in which either: main elementthat is, the toothed bar or the frame carrying the operative mechanisnkhas a step-by-step movement which is actively operative in one direction to move or raise a, load, and is passively operative in the opposite direction to lower the load or to "control its movement, whether the same actsvertically, horizontally,'curvilinearly, or in other direction. I

What I claim as my invention, and desire; to secure by Letters Patent, isv 1. In a jack, the combination of a barhav-i ing teeth on one face thereof,'a pivotal hand-i lever, two pawls pivoted thereto, and a'lever; carried'by the outer pawl and'having an arm; provided with an inclined lower face extend; ing over and bearing on the top of theshoul-i der on the inner pawl and the other end bear-i in g against a shoulder, so that when the inner pawl is raised and the outer pawl is lowered the upward movement of the inner pawl and the'downward movement of the lever will, through said lever, withdraw the outer pawl, substantially as and for the purposes set forth.

2. In a jack, the combination of abar having teeth on one face "thereof,a pivotal handlever, two pawls pivoted thereto, one pawl having a finger or shoulder thereon and the other-pawl having a tripping-lever pivoted directly thereto and having onearm bearing on the shoulder of theinner pawl, anda yielding tripping-plate having a shoulder with which the other end of said tripping-lever engages, substantially as and for the purposes set forth.

4 3. In'a jack, the combination of a bar having teethon one face thereof, a pivotalhandlever having a pawl engaging with said toothed bar, a slidable tripping-plate mounted on the jack-frame and having a spring pressing against the same tohold it in its operative position, and a withdrawing device to hold said plate away from engagement with said pawl, substantially as and'forthe purposes set forth.

4. In jacks,the combination of a toothed bar, a frame having a pivoted hand-lever mounted therein, a pawl mounted in such hand-lever and having a finger rigid therewith, the slidable tripping-plate g, having a shoulder engaging with said finger, and having slots through which bolts pass into the jack-frame, and provided with a pin extending out at the rear'thereof, and a spiral spring fitting within a seat in the jack-frame, into which saidpin enters,substantially as and for the purposes set forth.

5. A hand-lever for a lifting-jack, having flanges integral with the body thereof and extending up from the same, a seat extending through such flanges and along the body of the handle, and a slot formed in one flange, in combination with a pawl having its bearings integral with and formed at the base thereof, said pawl entering the seat through said slot in the flange, substantially as and for the purposes set forth.

In testimony whereof I, the said JOSIAH BARRETT, have hereunto set my hand.

JOSIAH BARRETT.

Witnesses: v

Row. D. TOTTEN,

JAMES I. KAY.

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