US511923A - Josiah babrett - Google Patents

Description

(No Model.)

J.BARRBTT.

IMK. v

Patented Jan. 2, 1894.

llNiTnD STATES arent @ninna J OSIAH BARRETT, OF ALLEGHENY, PENNSYLVANIA, ASSIGNOR TO THE DUFF MANUFACTURING COMPANY, OF SAME PLACE.'

J AC K SPECIFICATION forming part of Letters .Patent No. 511,923, dated January 2, 1894.

Application filed March 3, 1893. Serial No. 464,606. (No model.)

To all whom, t may concern:

Be it known that I, JosIAH BARRETT, of Allegheny, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Jacks; and I do hereby declare the following to be a full, clear, and exact description thereof.

Myinvention relates to jacking mechanism, and especially to that class of jacks in which a step-by-step movement back and forth is obtained', said mechanism being actively operative in one direction to raise or move aload, and passively operative in the other direction to control the movement of a load, such as in lowering a load lifted by the jack or controlling the backward movement where the jack 1s operated in horizontal or like positions, such as in oil well jacks.

My invention relates to the same general class of jacks as set forth in patents previously granted to ine, such as Letters Patent No. 312,316, dated February 17, 1885, No. 455,993, dated July 14, 1891, and others.

It comprises, generally stated, a rack or bar having teeth on one side thereof, aframe, a hand lever pivoted in the frame and carrying one or more operative pawls, and suitable reversing mechanism operating with the pawl or pawls for reversing the movement of the pack., the frame ofthe jack having a face pro- Jecting forward in the course of the upper or free end of the pawl forlimiting the outward movement of the pawl and so insuring its engagement with the rack or toothed bar, so that on the backward movement of the jack, while the pawl maybe held from the toothed bai' in such way as to insure it passing the tooth, it shall be properly directed into engagement with that bar when freed from the reversing mechanism holding it Vfrom engagement therewith.

It also comprises suoli a jack having the two operative pawls mounted in the hand lever, the outer pawl being provided with a nose or projection in the lcourse of the inner pawl to direct such pawl into engagement with the toothed bar.

It also consists in certain other improvements in the reversing mechanisin,as hereinafter described.

To enable others skilled in the art to make' and use my invention,l will describe the same more fully, referring toA the accompanying drawings,`in which- Figure 1 is a side view, partly broken away, illustrating the position of the'parts during the reversing movement of the jack and showing the engagement of the outer pawl with theV projecting face on the jack frame. Fig. 2 is a like view illustrating the position of the parts where the inner pawl is being directed by the nose on the outer pawl into engagement with the toothed bar. Fig. 3 illustrates the invention where another forni of reversing mechanism is employed, and Fig.4 is a detail view of the outer pawl.

Like letters indicate like parts in the several figures.

The general body or frame of the jack, illustrated at A, corresponds generally, eX- cept as hereinafter pointed out, with the jack frames shown in the patents above referred to, it being understood that where the frame is made movable upon the toothed or rack bar its form is somewhat changed, according to the direction of motion, a suitable form of the same being illustrated in the patent to XV. Forgie,No.122,879, dated March 4C, 1890. The frame A has a suitable passage or guideway for the toothed bar B, and where said bar is movable it has the foot b which fits within the ordinary slot formed in the forward face of the jack frame. The bar B has the teeth l) formed only on one side thereof, so that the two pawls will engage withthe saine rack face. The frame A has formed therein the socket oi' bearing a for the reception of the inner end of the operating or hand lever C, which hand lever has mounted therein the two operative pawls d e, these pawls being preferably arranged one on each side of the fulcrum pin c of the hand lever. The inner pawl e is mounted forward of the fulci'um, and hence is adapted to engage with and raise the toothed bar when the hand lever C is lowered, and the outer pawl d is mounted back of the fnlcrum pin and is of greater length than the pawl e, so that it engages with the toothed bar above the same and is adapted to engage with and raise the toothed bar when the hand lever C is raised. These are all the necessary parts for the operation IOO of raising the load or where the jack is actively operative, as in pushing, and are illustrated in the above patents.

The principalpo'int of myinvention relates to the jack when operated in lowering the load, or in its backward movement for controlling the movement of a load. For the purpose of lowering the load it is of course necessary that the pawls shall be withdrawn from the rack and held forward until they pass one tooth, andY that they shall then be properly directed into contact with the rack 1n order to engage the same. For this purpose two general classes of mechanism have been employed, one in which spring levers were mounted upon the pawls and engaged wlth a tripping plate, so called, which was capable of adjustment into and out of the course of the spring levers, according as the jack was lowered or raised, respectively, but when engaging with said levers was held rigid so that as the pawl held in engagement with the rack was lowered, its spring lever would engage with the tripping plate and the spring on said lever be compressed so that as soon as the pawl was freed from the rack (which was then held by the other pawl) the spring would draw it from engagement with the rack and hold it forward until the pawl had passed the tooth, when as the pawl was raised its lever would be freed from said tripping plate and it would engage with the toothed bar; this general form of mechanism being illustrated in Patent No. 312,316. Figs. 1 and 2 of the present drawings show spring levers which perform this function, but which are changed in certain particulars hereinafter described. rlhe other construction of jack had rigid 'fingers extending out from the pawls, and the tripping plate was made yielding, and these fingers, in the downward movement of the pawls, would engage with the tripping plate and would force that plate back and as soon as each respective pawl was relieved from the load the yielding tripping plate would, by the power stored, lift the pawl and hold it from engagement until it passed the next tooth; this mechanism being shown in Fig. 3 of the present drawings, and being illustrated in Patent No. 455,993.

It is evident that to insu re the proper movement of the jack the pawls must be first held from engagement with the rack until they pass the tooth and then directed into engagement therewith so as to take the load, and the present invention has for its special object the insuring of this result. For this purpose I form on the jack frame above the course of the upper or free end of the outer pawl the projecting face f, which face limits the outward movement of the pawl so that as soon as it is freed from the tripping plate, either through the spring levers or the pins above described, it will be directed by such projecting face into engagement with the teeth of the rack, the upper or free end of the pawl traveling along this face which is preferably curved and inclined, as shown in the drawings, and so being directed into engagement with the teeth of the rack.

For the purpose of directing the inner pawl e into engagement with the rack under the same conditions,I provide upon the outer pawl d the nose g which is so located that as one pawl is rising and the other lowering the inner pawl will, if necessary, contact with this nose or projection and by traveling over the same be directed so as to engage with the rack bar. By such construction it will be seen that the outward movement` ofthe pawls is limited or controlled so as to insure their inward movement to engage with the rack at the proper time, and by providing means to insure this result I am enabled to employ stronger spring mechanism for lifting or raising the pawls, which spring mechanism will therefore insure the pawls being held from engagement with the rack so as to pass the teeth thereof, and by means of the face f and nose g the outward movement of the pawls under the pressure of such springs, is controlled or limited, and

their proper engagement with the rack bar at the proper moment is insured, a positive movement of the operative parts being obtained for these reasons.

In Figs. 1 and 2 of the drawings I have illustrated certain changes in the construction of the spring levers, the spring lever hbeing mounted upon the pawl d, and the spring lever t' being mounted upon the pawl e, the lower ends of said spring levers engaging with the tripping plate 7c which is mounted upon the jack frame and made adjustable thereon by means of the eccentric Z, so as to be brought into and held in operative position when it is desired to give the backward movement to the jack, the tripping plate having the shoulder m with which the spring lever h engages, and the shoulder n (shown in dotted lines) with which the lever i engages. The springs are mounted around the pivoted pins of these 1evers and secured both tothe pawls and to the spring levers. In order to limit the movement of these levers and hold them in position to engage with the shoulders of the tripping plate, I form stops on the pawls themselves, the Stopp on the pawl d acting to limit the movement of the lever 7?., and the stop r on the pawl e acting to limit the movement of the lever i, a simpler constructionrequiring shorter levers being obtained in this way than is shown in said Patent No. 312,316, in which an abutment is provided upon the jack frame to hold said levers in position,and the lever on the inner pawl is necessarily held in position by contact with the lever on the outer pawl. The construction shown in Figs. 1 and 2 of this application operates to give all the necessary movements of such spring levers where the inward movements of the pawls are directed by the projecting face f and nose g above described. Where the jack is constructed as shown in said Figs. 1 and 2, the raising operation or forward movement of the jack is the same as IIO in said patents referred to. When, however, the jackis tobe given thebackward movement, the tripping plate k is brought into position as shown in said figures, and as the pawl d is drawn backwardly its spring lever contacts with the shoulder m and the spring is compressed until the pawl e takes the load and the pawl d is free from the rack, when the spring lever draws away the pawl and holds it from the rack until the pawl in its forward movement carries the spring lever away from said shoulder and in its course the upper or free end of the pawl contacts with the projecting facef which directs the pawl into engagement with the rack, and that pawl then takes the load. Meanwhile, the spring lever t of the inner pawl e has come into engagement with the shoulder n of the tripping plate and its spring is compressed, and as soon as the pawl d takes the load the pawl e is free and commences its forward movement, being held from engagement with the rack by the spring lever. As this pawl is being raised the other pawl is being lowered, and when the inner pawl comes into proper position to engage with the rack the nose on the outer pawl is brought into such position that it will direct the inner pawl into engagement with the rack and that pawl is so caused to engage with the rack and take the load, when the operation above described as to the outer pawl takes place.

The reversing mechanism shown in Fig. 3 is the same as described in said Patent- No. 455,993, the outer pawl d having the finger s, the inner pawl having the finger t, the tripping plate ubeing pivoted to the jack frame, and the spring p pressing against said tripping plate; and in the lowering operation the finger on the outer pawl contacts with the shoulder u of the yielding tripping plate and forces the tripping plate back until that pawl is freed from the load, when the yielding tripping plate will force it out and that pawl travels upwardly until its iinger is freed from the tripping plate and it is directed by the projecting face f into engagement with the rack and takes the load. Meanwhile, the inner pawl has been lowering and its finger t contacts with the shoulder u2 on the yielding tripping plate, compressing that plate until the pawl is freed from the load when the yielding tripping plate forces out the pawl and holds it out until it passes the tooth on the rack, and as the inner pawl rises and the outer pawl descends, the nose g will be brought into position to direct the inner pawl into engagement with the next tooth of the rack.

It is evident that the projecting face f on the frame and nose g on the outer pawl may be employed with any suitable construction of reversing mechanism. I am thus enabled by means of the improvements above described to employ mechanism for raising the pawls of sufficient strength to insure their being held from engagement with the rack until the pawls pass the respective teeth on the rack, being enabled to employ more powerful mechanism for this purpose; and, at the same time, I insure the engagement of the teeth with the rack and provide a more positively operating jack. I am also enabled to simplify the spring lever mechanism upon the pawls.

I am aware of Patent No. 399,470, granted to me March 12, 1889, for lifting jacks, but that patent does not show the invention desired to be covered herein, that patent showing a detent mounted on the jack frame, the function of which is to hold the tooth bar when moved by the pawl mounted in the hand lever, such detent not having any movement of its own and simply swinging on its pivotal bearing on the jack frame, and not having any projecting face which acts to direct the pawl into engagement with the tooth bar.

W'hat I claim as my invention, and desire to secure by Letters Patent, is-

1. In a jack, the combination of a rack having teeth on one side thereof,a frame,ahand lever pivoted therein, a pawl pivoted to said lever, mechanism for holding the pawl from engagement with rack, and a projecting face in the course of the pawl, for limiting the outward movement of the pawl and directing it into engagement with the rack, substantially as set forth.

2. In a jack, the combination of a rack having teeth on one side thereof, a frame, a hand lever pivoted therein, a pawl pivoted to said lever, mechanism for holding the pawl from engagement with the rack, and a projecting face' on the jack frame in the course of the pawl, for limiting the outward movement of the pawl and directing it into engagement with the rack, substantially as set forth.

3. In a jack, the combination of a rack having teeth on one side thereof, a frame, a hand lever pivoted therein, two pawls pivoted to said lever, mechanism for holding said pawls from engagement with the rack, and a nose on the outer pawl in the course of the inner pawl for limiting the outward movement of the inner pawl and directing it into engagement with the rack, substantially as set forth.

Ll. In a jack, the combination of a rack having teeth on one side thereof, a frame, a hand lever pivoted therein,two pawlspivoted to said lever, mechanism for holding said pawls from engagement with the rack, a curved face projecting from the jack frame in the course of the outer pawl, and a nose on the outer pawl in the course of the inner pawl, substantially as set forth.

5. In a jack, the combination of a rack having teeth on one side thereof, aframe, ahand lever pivoted therein, a pawl pivoted to said lever, a spring lever mounted on said pawl, a stop on said pawl for said lever, and a shoulder in the course of the lever, substantially as set forth.

lOO

6. n a jack, the combination of a rack havlng teeth on one side thereof, a. frame, a hand lever pivoted therein, wpawl pivoted to said ievena 'spring lever mounted on said pawl, a 5 stop on said pawl for said lever, a shoulder` in the course of the lever, and a projecting face 1n the course of the pawl for limiting the outward movement of the pawl and directing it into engagement With the toothed bei, substantially as set forth. 1o

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

. JOSIAH BARRETT. Witnesses:

J. N. COOKE, D. L. DoRsEY.

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