US1786754A - Lifting device - Google Patents

Description

2 shees-sneex 1 //V VE /V TOR. //V 1/. l. H0 TT l. VON K. HOTT LIFTING DEVICE Filed Jan. 5, 1927 TTFPNEY Dec. 30, 1930.

Dec. 30, 1930. l. VON K. HOTT LIFTING DEVICE Filed Jan. 3, 1927 2 Sheets-Sheet 2 ATTOR/VE Y l XA su" im Patented Dec. 30, 1930 PATENT orrilce UNITEDY STATES ION VON KERT HOTT, OF DAYTON,`OHIO, ASSIGNOR T0 THE JOYCE-CRIDLAND COMPANY, OFDAYTON, OHIG, A CORPORATION OF OHIOr LIFTING DEVICE Application filed January 3, 1927. Serial No. 158,639.

This invention relates to lifting devices and more particularly to a pawl and ratchet )ack of the type shown in the application for patent tiled by Hott and Spear on February 2,'

` pawls to control their positions with relation to the toothed element.

The object of the present invention is to provide in such a jack means whereby both pawls may be moved to their inoperative positions to permit the lifting elementto move quickly to its lowermost position.

A further object of the invention is to provide such a device which will be very simple in its construction and operation and which will be of such a character and so arranged that it will not in any way interfere with the operation or handling of the jack.

Other objects of the invention will appear as the device is described in detail.

In the accompanying drawings Fig. 1 is a side elevation, partly broken away, ot a litting jack embodying my invention; F ig. 2 is a vertical sectional view ot sucha ach, partly broken away; F ig. 3 is a side elevation orP the upper portion of the jack, partly broken away to show the lifting pawl in its elevated position; and Fig. l is a similar view showing the tripping device in its operative position.

In these drawings l Vhave illustrated one A embodiment of my invention and have shown the same as comprising a base 1 on which is mounted a vertical standard 2 having a guideway in which is slidably mounted a toothed element 3. ln the present instance, l have shown the invention as applied to a pole jaclr andV the upper end ot the lifting element is claw shaped, as is customary in such jacks, and the standard 2 is pivotally mounted at 4 on the base and is held normally in its upright position by means ot' a latch 5 having an actuating arm 6.

Pivotally mounted on the standard 2, in front of the toothed element 3, is a pawlcarrier which is here shown` as comprising a trunnion 7 having an enlarged portion 8 and provided with means for actuating the same, such as a lever socket 9 to receive the usual operating bar or lever. A lifting pa-wl 10 is pivotally mounted on the pawl carrier at 11, the point ot connection of the pawl with the pawl carrier, or enlarged portion of the trunnion7 being spaced some distance from the axis of the trunnion so that the movement of the latter will impart bodily movement to the pawl. This pawl has secured thereto and preferably formed integral therewith an apertured lug 12 which extends rearwardly and laterally therefrom. Pivotally mounted on the standard 2 above the trunnion 7 is a detent pawl 13 which is, also provided with a rearwardly and laterally extending apertured lug le. The lugs 12 and 1a are arranged with their apertures in alinement and a rod 15 is slidably mounted in said apertures. This rod has at its upper and lower ends stops 16 and 17 and at a point between its ends it is provided with a stop 18. The stop 17 is located below and adapted to engage the apertured lug 12 ot the lifting pawl and the intermediate stop 18 is located below and adapted to engage the apertured lug 11i of the detent pawl. A spring 19 is confined between the apertured lug 12 or" the lifting pawl and the intermediate stop 18 and a spring 2O is confined between the apertured lug 14 ot the detent pawl and the upper stop 16. Means are provided for depressing the rod 15 and holding the same in a depressed position during the lifting operation and this means is here shown as comprising a pivoted plate 21 adapted to engage the upper end oi the rod 15 and this plate is actuated by a finger 22 connected wth a pivoted operating handle 23. lWhen the rod is held in its depressed pos.: ion the springs 19 and 2O will be under compression and wilL tend to hold the pawls in engage ment withVr the toothed element. 17V hen the pawl carrier is operated to impart upward movement to the lifting pawl thev lifting element will be moved upwardly, the detentypa-wl yielding to permit the teeth of the toothed element to ride past the same, and when'the pawl carrier is moved downwardly the detent pawl will hold the toothed element against downward movement and the lifting pawl will yield and ride over the teeth of the toothed element, thus permitting the load to be elevated step by step. lVhen it is desired to lower the load the locking plate 2l released and the springs will move the rod into the position shown in Fig. l. As there shown, the detent pawl is in engagement with the toothed element andthe lifting pawl has been moved out of engi` gement th with by the contact ot' the lower stop li' n t i the apertured lug l2. l/Yhen the "awl carrier is artuated to move the lifting pa wl upwardly this pawl will more relatively to the toothed element but it moves iipw'ai."ly the spring 19 will be placed under compression and will rock the pawl about its individual axis ll to cause the nose their-zotl to engage the toothed element, the rod tilting to permit of the move'- nient of the pawl. The movement is so timed that the lifting pawl will engage the toothed element just before the pawl completes its upward movement and the final movement ot' the pawl will impart a slight upward nievement to the toothed element, thereby releasing the detent pawl and permitting the saine to be moved to its inoperativeposition by the action of the spring i9 and stop 18 on the lug la of the detent pawl. The load is then carried by the lifting pawl and as the pressure on the operating handle is relieved the load will move downwardly. As the toothed element and lifting pawl move downwardly trie lug l2 of the lifting pawl will engage the lower stop 17 on the rod and canse the rod to move -f downwardly, thereby causing the detent pawl to be moved toward the lifting element. This movement is so timed that the detent pawl will not engage the lifting element until one or more teeth of the toothed element have passed the pawl but it will engage the litting element and support the load just before the lifting pawl reaches its lowerinost position. The final downward movement ot the lifting pawl Vwill cause the lug l2 thereon to engage the lower stop 17 which will roch the pawl about its anis and move it out ot engagement with 'he toothed element. 'By repetition oit this eycle ol operations the lead may be lowered step by step.

The mechanism and operation above described enable the load to be raised and low-f ered step by step but it is sometimes desirable to lower the load quicklyj th at is, to permit the lifting element to move qui l; lowermost position. To accomplish this l have provided means whereby said pa wls may be moved to their inoperative positions7 thereby releasing the toothed element and permitting of the free downward movement thereof, either with or without load. In the present construction, the standard 2 ha s' termed therein a vert-ical guideway Q4 in whieh is slidab'ly mounted a tripping member 25, which is here shown in the orm of a bar or pl nger, the' upper end of which is arranged in line with and adapted to engage the lower end o'lz the rod l5. Preferably the upper end ol the trippinw plunger has an enlarged head 26 to provide it with sufiieient area to contact with the end ol the rod when the latter is in either its true vertical position or its tilted position. The lower end of the plunger has a laterally extending portion or foot 27 which is adapted to be engaged by an actuating cam 28 pivotally mounted at 29 on the standard Q. Connected with the cam is an operating nunnber7 here shown in the form of a handle l() and so arranged that when the cam is in its inoperative position the handle will extend alongside ot' the standard and close thereto. The cam 28 is so shaped that when the handle is moved outwardly7 and upwardly the can: will force the plunger upwardly and thus cause it to contact with the rod l5 and move that rod upwardly. The nose 3l ol the cani so arranged that when the cam isl in its uppermost or fully operative position the point ol contact between the plunger and the cam will be offset or arranged on the outer side olA the axis of the cam so that when the cam is released the pressure of the plnng r thereon will restore the cam to its inopeative position, thereby preventing the cam from being inadvertently left in a position which would render the mechanism inopeative.

lVhen the lool-:ing plate 2l released and the operating lever 9' is in its lowermost position the lifting pawl will be in engagement with the toothed element and the detent pawl will be in its inoperative position. lf the litting pawl has sullicient movement with relation to the pawl supporting member S the rod l5 m-ay be moved far enough to torce this pawl out of engagement with the toothed element, but where, as in the present instance. the movement of the pawl is limited the npward movementot the rod will not force the Apawl to its inoperative position but the tripping member will hold the rod in its elevated position so that. the downward movement of the pawl, when the operating lever is elevated, will canse the lug l2 on the lifting pawl to engage the lower stop 1T on the rod. thus rocking the pawl about its axis to an inoperative position and releasing the toothed element.

lllhen the operating lever is in its raised position the lifting pawl. will he in its ii'ioperative position and the datent pa wl in its operative position, and the upward movement im. parted to the rod by thev tripping device will force' the detent pawl out olf' engagement with the toothed element.

The actuating device 'li'or the plunger may be of any suitable character but, i n the p r'e sont instance, I have utilized 'for this purpose one of two carrying handles 30 which are pivotally mounted on the opposite si Tes et the standard 2 and are provided with s aces 32 arranged to? Contact with the sides' ot the' weaves standard and forni stops to limit the upward movement of the handles. One of the carrying handles is arranged beneath the plunger 25 and in order to utilize the saine as an actuating device for the plunger I have shaped the upper end thereof, beyond the surface 32, to provide the cam 28, which will en gage ant actuate the plunger when the handle is moved to its extended position.

While I have shown and described one embodiment of my invention I Wish it to be understood that I do not desire to be limited to the details thereof as various modifications may occur to a perso-n skilled in the art.

Having now fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. In a lifting device, a standard, a toothed element carried by said standard, a lifting paivl and a detent paWl supported on said standard and cooperating with said toothed element, means to actuate said lifting pa-Wl, a rod connected With and capable of longitudinal movement vvith relation to said paivls, springs carried by said rod and acting on said pavvls, means to control the longitudinal movement of said rod and thereby control the operation of said paivls, and other means to control the longitudinal movement of said rod to cause both of said paWls to assume inoperative positions with relation to said toothed element. V

2. In a lifting device, a standard, a toothed element carried by said standard, a lifting pavvl and a detentk paWl cooperating with said toothed element, means to actuate said lifting pawl, a rod connected with and capable of longitudinal movement With relation to said pa-Wls, springs carried by said rod and acting on said pavvls, means to control the longitudinal movement of said rod and thereby control the operations of said pawls, a tripping device to act on said rod to cause said paWls to be moved into inoperative positions, and means for actu ating said tripping device.

In a lifting device, a standard. a toothed clement carried by said standar-fl, a lifting paavl and a detent paivl cooperating with said toothed element, means to actuate said lifting pawl, a rod connected with and capable of longitudinal movement with relation to said pavvls, springs carried by said rod and acting on said paivls, a tripping device slidably mounted on said standard and arranged to engage said rod, and means for imparting sliding movement to said trip ping device.

ll, In a lifting device, a standard, a toothed elementcarried by said standard, a lifting paivl and a detent pavvl cooperating With said toothed element, means to actuate said lifting pavvl, a rod connected with and capable of longitudinal movement With relation to said pawls, springs carried by said rod and acting on said pavvls, a tripping device slidably mounted on said standard and arranged to engage said rod, a cam acting on said tripping device to impart sliding movement thereto, and means for actuating said cam.

5. In a lifting device, a standard, a toothed element carried by said standard, a lifting paWl and a detent paivl cooperating with said toothed element, means to actuate said lifting pavvl, a rod connected with and capablo of longitudinal movement with relation to said pawls, springs carried by said rod and acting on said pawls, a plunger slidably mounted on said standard, a cam pivotally mounted on said standard beneath said plunger and having a. contact portion offset from the axle thereof, and a handle operatively connected with said cam.

6. In a-lifting device, a standard, a toothed element carried by said standard, a lifting pawl and a detent paivl cooperating With said toothed element, means to actuate said lifting patvl, a. rod connected with and capable of longitudinal movement with relation to said pawls, springs carried by said rod and acting on said paWls, means for moving said rod in one direction to cause both paivls to be moved into operative relation to said toothed element, and means for moving said rod in the opposite direction to permit both pawls to be moved into inoperative positions with relation to said toothed element.

7 In a lifting device, a standard, a toothed element carried by said standard, a lifting pawl and a detent pavvl supported on said standard and cooperating With said toothed element, means for actuating said lifting paivl,'and means for controlling the positions of said pavvls with relation to said toothed element, said means comprising springs acting on said pawls, a rod having longitudinal movement with relation to both pavvls, means to limit the movement of said rod in one direction to cause both pavvls to operatively engage said toothed element, and means movable into and out of a position to limit the movement of said rod in the other direction and thus cause both pawls to be moved into inoperative positions with relation to said toothed element.

In testimony whereof, I affix my signature hereto.

IOl\T VON KER-T HOTT.

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