US1593364A - High-speed-screw jack - Google Patents

Description

July 20 1926. 1,593,364

F. H. SCHWERIN HIGH SPEED SCREW JACK Filed August 35', 1923 3 Sheets-Sheet 1 I E] venioz I v ZWA 3 M 35 3 6W7 July 20,1926. 1.593364 F. H. SCHWERIN HIGH SPEED SCREW JACK Filed August 25. 1923 3 Sheets-Sheet 2 avwewcoz F. H. SCHWERIN HIGH SPEED SCREW JACK July 20, 192 6.

3 Sheets-Sheet Filed August 25, 1923 39 36 .35 v avwnto'c 351g @lfliovm July 243, i925.

mart stares teases? this FRANK sonwniam, or WEST VEEW, renusvnvaum assreuon TO THE DUFF e or PENNSYLVANIA. V

This invention relates to the class of screw lit ing jacks known as high-speed jacks havrag screws of suiiic iently steep pitch to run down under the load. Various "forms of high-speed jacks are known and the teatu'res of the invention are not necessarily limited in their application but are illustrated in connection with the jack disclosed in the Kept & Schwerin Patent No. 1.329,- 665 of February 3, 1 920, for which they have been more particularly designed. The ohj'ectfi's, therefore, to provide certain tea tures of improvement whereby greater strength and increased ei'licieno'y and con ven'ience are secured.

fine of the features is an improved construction of the overrunning clutch between. the holding and lowering mechanism and the steep-pitch screw, another feature is an improved construction for he manually operatable el'ut'cl'i whereby the. lowering means can becoupl'ed with the screw for r positive lowering of the jack when without load, and still another feature has to do with an attached lowering handle, which is connjactly disposed when not in use.

In the accompanying drawings forming part hereof: v

Fig. 1 is a view, partly in elevation and partly in central vertical section of a aclt embodying the improvements;

Fig. 2 is a large fragmentary vertio'alsectional view looking at right angles to Fig. 1, the vertical shaft in the plane of section being' shown partly inelevation and partly broken away and in section;

Fig. Sis a detail view or an operating plui'i'ger and crosspin;

' Fig; e is an enlarged horizontal section onjthe line of Fig. 1;

Fig. 5 is a fragmentary elevation on an enlarged scale looking at the back of Eig. 1', and showing the lowering handle folded st the frame and 45 g, Sisa fra t s ctional elevation le sho g; the handle Otjt l in d I1 me and rises upward within MANUFACTURING oomrnur, or P TTSBURGH, snmrsvrivaurn, A ooaroaarrou HIGI-I-SPEED-SCREW JACK.

Application filed August 25, 1923. serial No. 'esaee rain 3, which carries a nut or hollow screw member 6 for cooperation with the screw Fastened on the'lower portion of the screw is a large spur gear 7, which rests upon ball- plates 8, 9 and interposed balls 10. The gear 7 is meshed by a pinion Lion the lower end ot a vertical shaft 12, which is j ourn'aled in bearings 13, 14 and 15 in an annex 16 of the base trains.

Fast on the shaft 12, above the pinion 11, is a bevel gear 17, which may be termed the lifter gear. This gear is meshed by a bevel pinion 1 8, whic'ln as shown in the Kop't S: Schwerin patent referred to, is operated by a long removable bar-lever 19 through oscillatory pawl and ratchet mechanisnn which it is not thought necessary to show here in detail since such matters arewell known.

A ratchet wheel 20 is fixed to the shaft above the bearing 1 k, and this is surmounted by a pawl-carrier wheel '21, which is rotatable on the shaft and has depending rini portions '22, which are opposite the periphe'ry ot' the ratchet wl'ieel. In the intervals 28 between these said portions 22 are pawls 24, preferably three in n'ijunber, pivoted on pins 25 to engage with the teeth of the ratchet wheel, which have sloping backs, so that the two parts of the overrunning clutch thus constituted are free to rotate relatively to each other in one sense or direction while having" driving or holding engagement in the reverse sense. One of the features of the ihv'ention has to do with this overrunn'ing clutch, which is interposed between the shaft 12, and therefore the SCIQV, on the one hand, and the holding and lowering means, to be described, on the other hand.

It will be seen in Fig. e that each of the pawls 24 is provided with a tail 26 projecting rearward from its pivot, that is to say reversely to the body of the pawl. The riin portions 22 of thepawl-carri'er 21 are armed to allow clearance for these tails, aiid are -"ovided with seekers 27 in their hare opposite the inner sides of lls. The tails themselves are Irostuds 28 projecting from tfiei'r sockets, and com Seb eoi1spririgs 29 re entered iILthe are 27 with their outer ends engaged over ehejstuds '28} These s rings constantly depress the so to bear upon the ratchet wheel, the construction being such as to avoid the operation of the jack being impaired or destroyed through the failure of the springs of the overrunning clutch. The ends of the bodies of the pawls are preferably formed with two teeth 30, instead of one tooth as heretofore.

The holding and lowering means is prefcrably, though not necessarily, of the kind comprising a worm wheel 31 meshed by a worm the pitch of the gear being such that the wheel 31 which encircles the shaft 12 can not drive the worm 32. Consequently. if the wheel 31 is connected with the lifting screw, the load can not descend unless the holding worm is rotated in the proper direction. The jack is nevertheless virtually self lowering in the sense that the weight or the load drives the jack down and operates all the mechanism up the holding device 32. which is simply let off by hand. The advantage of this particular form of holding" and lowering means is safety, since the jack can not run away or start down unintentionally.

As shown, the worm wheel 31 is united with the pawl-carrier 21, and the arrange- .ient of the overrunning clutch 20, 21, Ed is such that the screw 5 and the shaft 12 geared thereto can be operated by the lifting' lever 19 for lifting without rotating the worm wheel 31, that is to say inde pendently of the holding and lowering means. At the conclusion of each lifting movement. however, descent is prevented through the positive engagement of the parts of the overrunning clutch so that the effort exerted by the load is transmitted to and res -tted by the holding means.

The worm 32 occupies a lateral boss or enlargement 33 on the frame annex 16, and its shaft or journals are mounted in suitable hearings. one of which is a gland 3.4 screwed into the outer end of the boss 33 containing a bearing 35 for the journal end 36. A. crank handle. 37 constitutes the means for manually rotatingthe lock or holding device 32, so as to permit the jack to lower. The same handle can also be used for rapidly running the jack up to the load. Heretofore this handle has been a separate piece, adapted to he Focketed to the journal end of the worm. and for this reason it has not als been at hand when needed. and in the present improven'ient an elbow 38 is pinned it 39 to the journal 36 so that its outer 'iortion -t0 projects at right angles to its avial portion. The end of the bentportion i0 is bifurcated and receives the inner end of the crank handle proper 37. A pivot pin 41 passed transversely through the parts of this region rigidly connects the handle proper and the elbow for rotary operation, and permits the handle to be folded over the hos 33, where it will be confined by a projecting from the top of the boss ear the wall of the annex rising above boss, seen in Fig. In the operaposition the shank of the handle proper 15-. turned outward, so as to form a continuation of the bent portion 40 of the elbow. Curved notches l2, :1 quadrants distance apart on the hub 43 of the handle proper 37. cooperate with a non-positive locking plunger ll pressed from a bore if) in the elbow portion it) by a spring it), so that the handle held tirmly, though yieldingly, in each of its positions. The folding construction of the crank handle of the lowering worm not only connects the handle p rm nently to the jack frame, while enahlin y it to be folded compactly out of the way against the frame, but also has the fur ther advantage that if the handle should be left unfolded while the jack is wheeled about in a rearwardly tilted position, the handle will not become bent or interfere with the \i'heclingby coming in contact with the around. it will be seen in Fig. 1 that if the jack should be tilted backward so that the end of the handle bore forcibly against the ground, the pivotal joint -ll would au tomatically bend in a perfectly safe manner. lVere it not for this joint, the handle or the loweringmechanism controlled thereby might. easily be injured so as to render one of these large jacks, which are used for jacking: up locomotives and heavy cars, either inoperative or unsafe.

lVhile the jack runs down by gravity, as permitted by manipulation of the holding and lowering means, it is nevertheless desir able to provide means for positively lowering or driving down the jack in case the weight of the lifting member alone, when the jack is unloaded, should not be sutiicient to overcome friction, or in case at any time sticking might occur when it is desired that the load member shall be set. For this reason means are provided, as in the Kopf & Schwerin patent aforesaid, for positively coupling the rotary holding and lowering mechanism to the shaft 12, and therefore to the screw. in respect to lowering movement; when desired. This means includes :1 normally spring-disengaged and mamuilly-engageable clutch between the holdin; and lowering means of the shaft 12. Specifically the worm wheel is provided with a crown of ratchet teeth 47, adapted to be engaged by a ring of corresponding teeth 48 on the depending rim of a clutch disk 49, which is engaged with ribs 50 on an upper part of the shaft 12 so as to be movable longitudinally thereon into and out of engagement with the teeth 47 while held againstrotation relatively to the shaft. A spring 51, interposed between the clutch member 49 and the worm wheel 31, normally holds the clutch element separated. Thus far the clutch is like that disclosed in the Kopf & Schwerin patent, but improved means are provided for its manual operation.

In the present construction the upper end portion of the shaft is drilled with a longitudinal bore or passage 52, which extends from the upper end to a point within the worm whee-l. A transverse bore or passage 53 is also formed in the shaft intersecting the bore 52. An operating button projects at the top of the frame annex 16 and has a stem 55 which passes through an opening in a top plug 56 and downward into the longitudinal passage 52 in the shaft. This stem has a transverse hole through it, through which and through the passage 58 a cross-pin 57 is inserted with its ends projecting at opposite sides of the shaft. The

ends of the pin rest upon the top of the longitudinally movable clutch member 51, and the pin is movable transversely to itself in the passage 53, which is considerably larger than the pin. The pin consequently forms the intermediary between the plunger 55 and the clutch member 49, so that downward pressure of the hand upon the button 54 will engage the clutch member 49 with the clutch teeth 47. When the hand is removed, the pressure of the spring 51 automatically raises the clutch member 49 and the plunger. This construction is very simple and is more serviceable than the construction disclosed in the Kopt & Schwerin patent, wherein the yoke there employed straddling the end of the shaft would sometimes become deranged. The projecting ends of the cross-pin 57 may lie in a circular depression 58 in the top of the. clutch member 49, which will preventendwise displace ment of the pin.

What I claim as new is:

A lifting jack in which there is a steeppitch lilting screw, a shaft geared to said screw, holding; and lowering mechanism and a'rotary lowering handle, an automatic overrunning clutch between said mechanism and shaft, and a manually operatable clutch hav ing a spring-disengaged member movable longitudinally of the shaft whereby the lowering means can be coupled to the shaft for positive lowering when desired, characterized by said shaft having intersecting longitudinal transverse passages in its end portion, an operating button having its stem working in the longitudinal passage of the shaft, and a cross-pin movable laterally to itself in the transverse passage and acting as the intermediary between said stem and the manually-operatable clutch member.

' FRANK H. SCHVJER-IN.

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