US1702442A

US1702442A - Lifting device

Info

Publication number: US1702442A
Application number: US6318A
Authority: US
Inventors: Ion V K Hott; Walter A Spear
Original assignee: JOYCECRIDLAND Co
Current assignee: JOYCECRIDLAND Co
Priority date: 1925-02-02
Filing date: 1925-02-02
Publication date: 1929-02-19
Anticipated expiration: 1946-02-19

Description

5 Sheets-Sh'get l.

IN VEN TOR. /0/7 K A. l/a rr ,la rnv ff. JPI

A TTORNEY l. K. HOTT ET AL LIFTING DEVICE Filed Feb. 2, 1925 Feb. I9, 1929'.

Patented Feb. 19, 1929.

UNITED STATES ON V. K.'HOTT AND WALTER A. SPEAK, 0F DAYTON, OHTO, ASSGNORS TO THE JOYCE- PATENT s oFFlcE.

CRIDLAND COMPANY,`OF DAYTON, OHIO, A CORPORATION OF OHIO.

LIFTING DEVICE.

Application mea February 2, 1925. serial No@ 6,318.

This invention relates to lifting devices and more particularly to the type of lifting device known as a double-acting pawl and ratchet jack.

One object of the invention is to provide improved means for controlling the operation of the pawls of such a ack.

A further object of the invention is to provide controlling means for said pawls which will insure their accurate and positive operation and thus positively control the load on v the jack. n c

A further object of the invention is to -provide such a controlling means which will be simple in construction, inexpensive of manufacture and which will not be easily broken or disarranged in operation.

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

ln the accompanying drawings Fig. 1 is a side elevation of a jack embodying our invention; TEig. 2 is a front elevation of the same, partly broken away; Fig. 3 is a sectiontalren on the line 3 3 of Fig. 2, showing the pawls in their lifting positions;-Fig. 4 is a similar section showing the pawls in their initial low-` ering positions; and Fig. 5 is a detail view showing the pawls in their elevated lowering positions.

In these drawings we have illustrated one embodiment of our invention and have shown the same as applied to a ack of the pawl and ratchet type embodying a lifting element haviney teeth with which the pawls may be engaged, but it will be understood that the invention may take various forms andinay be applied to pawl and ratchet jacks of various kin ds regardless of whether or notthe toothed element constitutes the lifting element or-is separate therefrom. f

In that embodiment of the invention here shown the j ack comprises an upright hollow standard or supporting frame 1 having'its lower end enlarged, as shown at 2, to constitute a base. Slidably mounted in thisjack is a lifting element 3 having at its upper end a load engaging member or cap 4. In the present jack, the lifting element is in the form of a bar and is provided in one edge with ratchet teeth, as shown at 5. Mounted on the standn ard or supporting frame 1 is a pawl supporting'member which, as here shown, comprises a trunnion 6 journaled in the side members of the supporting frame and having an enlarged central portion 7 on which thelifting pawl is mounted. Connected with the pawl supporting memberis an actuating member which is here shown in the form of a lever socket 8 krigidly secured to the pawl supporting member and adapted to receive the usual hand lever, by means of which the jack is opy ranged 'above the lifting pawl!) -is a detent pawl 11 which. askhere shown, vis pivotally mounted on a shaftor trunnion 12 mounted inthe sidewalls of the supporting frame and is movable about-.the axis of said trunnion into and out of engagement withthe teeth of the lifting member. The pawl is, in the present instance, provided with a double nose, as shown at 13, so that it will engage two teeth on the toothed member. Extending alongside of the lifting element 3 is a bar 14 which is connected with, but is capable of movement relatively to, both the lifting pawl 9 and the detent pawl 11, and associated with this bar aresprings which act on the respective pawls to control the positions thereof. The lifting pawl 9 has rigidly secured thereto, and'preferably formed integral therewith, an apertured lug 15 and the detentpawl has rigidly secured thereto and preferably formed integral therewith an apertured lug 16. The

rod 14 is mounted in these apertured lugs for both longitudinal bodily movement with relation to the lugs and for tilting movement in the lugs. `As here shown, thelugs extend rearwardlyand laterally fromthe respective pawls so that the barc14 is supported alongside of the lifting element. The bar 14 has secured thereto, substantially midway between its ends, a stop, which is preferably the form of a collar 17 rigidly secured to the bar. At its lower and upper ends the bar has secured thereto other stops which, in the present instance, are in the form of nuts 18and 19 screwthreaded onto the ends of the bar so as to provide adjustable stops. The apertured lug 15 of the lifting pawl embraces the bar 14 above the lower stop 18 and a spring 20 is coiled about the bar between the lug 15 *and the intermediate stop 17. The apertured lug 16 of the detent pawl embraces the bar above the intermediate stop 17 and a spring 21 is coiled about the bar between the lug 16 and the upper stop 19. In the operation of the present jack the bar 111 is held against vertical movement during the lifting operation and to this end a suitable stop is provided which may be moved into and out of the path of the bar. As here shown, this stop is in the form of an elongated plate 22 pivotally mounted at its rear end on the supporting frame or standard 1 and having its forward portion 28 inclined with relation to its rear portion to form a contact member which is adapted to be engaged by a dog 24 pivotally mounted on the forward portion of the standard and provided in front of the standard with an operating` handle 25. lf desired, the standard may be provided, adjacent to the handle 25, with a fixed hand grip 26 to facilitate the handling of the jack and to guard the handle 25.

When the stop plate 22 is moved into locking position with relation to the bar 14, as shown in Fig. 3, that bar will be forced downwardly, so that the

stops

18 and 17 will bc spaced from the

apertured lugs

15 and 16 and the

springs

20 and 21 will be placed under compression so that they will act upon the lugs 1.5 and 16 to hold both pawls in operative engagement with the toothed element. Consequently when oscillatory movement is imparted to the lever the upward movement of the lifting pawl will elevate the lifting element, the detent pawl yielding to permit the passage of the teeth on the lifting element. Upon the reverse or downward movement of the lifting pawl the detent pawl will be retained in engagement with the teeth and will support the lifting element against downward movement, while the lifting pawl will ride over the teeth of the lifting el ement.

When the load is to be lowered the locking plate 22 is released so that it offers no resistance to the movement of the bar 14. In Fig. 11 the pawls are shown in their initial lowering positions, that is, the locking plate has been released and the pawls are ready for the lowering operation. rll`he detent pawl 11 is in engagement with the teeth of the lifting element and these teeth overhang` the nose of the pawl in such a manner that it cannot be moved about its axis without imparting vertical movement to the lifting element. The spring 21, which is confined between the upper stop 19 on the bar 1% and the lug 16 of the detent pawl, serves to hold the bar in its upper position with the stop 17 in engagement with the lug 16 and the lower stop 18 in engagement with the lug 15 of the lifting pawl 9, which is in an inoperative position. When the actuating lever is moved downwardly upward movement will be imparted to the lifting pawl and inasmuch as the bar 14; is held against upward movement by the stop 17 engaging the lug 16 the lower spring 2G will be placed under compression and this compression increases the nose of the pawl will be moved into engagement with the teeth of the lifting elei'nent, the lower end of the bar swinging over or tilting to permit of this movement of the pawl. lhe parts are so shaped and arranged and their movements so timed that this lifting pawl will engage the toothed clement just before the lever completes its downward movement and, having engaged the toothed element, the further downward movement of the lever will cause the pawl to impart a slight elevation to the lifting element. This upward movement of the lifting element is sufficient to release the detent pawl 11 and the action of the lower spring 2() on the stop 17 will move the bar 1li upwardly and thus swing the detent pawl away from the lifting element into an inoperative position. The vload is now carried wholly on the lifting pawl and as the pressure on the operating lever is relieved both the lifting element and the lifting pawl will move downward together. As the lifting pawl moves 'downwardly the tension on the spring 2O is relieved and the lug` 15 on the lifting pawl engages the lower stop on the bar and moves that bar downwardly, fliers-bj,r exerting pressure on the upper spring 21 and causing that spring to a'ct on the lug 16 of the detent pawl to move the detentpawl into engagement with the toothed element. This movement is so timed that the det-ent pawl will not be moved into operative position until one or more of the teeth of the lifting element have passed the same. Having been brought into operative position the detent pawl will check the further downward movement of the toothed lifting element and the upper spring 21 will resist the further downward movement of the bar 141-. The continued downward movement of thev lifting pawl, as the operating lever completes its upward movement, will cause the lug 15 of the lifting pawl to engage the lower stop 18 on the bar and rock the pawl about its axis into an inoperative position, thus restoring the parts to their initial lowering positions.

Cil

The repetition of this cycleV of voperations i causes the load to be lowered step by step. v

While we have shown and described one embodiment of our invention we wish it to be understood that we do not desireto be limited to the details thereof as various modifications may occur to a person skilled in the art. f

Having now fully described our invention, what we claim as new and desire to secure by LettersPatent, is: v

1. In a lifting device, a toothed element, a pawl supporting member, a lifting pawl carried by said supporting member and movable into and out of lifting engagement with said toothed element, means for actuating said supporting member to impart bodily movement t-o lsaid lifting. pawl, a detent pawl mounted independently of said lifting pawl 'and also movable into and out of engagement with said toot-lied element, a rigid bar slidably mounted on said paivls longitudinal moven'ient with relation thereto, means for limiting the movement of said bar with relation to said pawls, and springs carried by said bar and acting on the respective pawls to control the positions thereof with relation to said toothed element.

` 2. In a lifting device, a toothed element, a pawl supporting member, a lifting pawl carried by said supporting member and movable into and out of engagement with said toothed element, means for actuating said supporting member to impart b -dily movement to said lifting pawl, a detent pawl mounted independently of said lifting element and also movable into and out of engagement with said toothed element, a rigid bar supported by said pawls andcapable of longitudinal movement with relation thereto, stops carried by said bar, lugs carried by the respective pa wls in fixed positions with relation thereto, and springs confined between said stops and the respective lugs to control the positions of said pawls with rela ion to sait toothed element. 3. In a lifting device, a toothed element, a pawl supporting member, a. lifting pawl carried by said supporting member and movable into and out of engage-ment with said toothed element, means for actuating said supporting member toimpart bodily movement to said lifting pawl, a detent pawl mounted independently of said lifting pawl and also movable into and out of engagement with said toothed element, a rigid bar connected with and capable of longitudinal bodily movement with relation to both of said pawls, springs acting on said bar to impart longitudinal movement thereto, and means to control the` longitudinal movement of said bar with relay tion lto said pawls and thereby control the action of said springs on said pawls.

4l. In va lifting device, a toot-lied element, a

pawl supporting member, a lifting pawl carried by said supporting member' and movable into and out of engagement with said toothed element, means for actuating said supporting member to impart bodily movement to said lifting pawl, a detent pawl mounted in` dependently of said lifting pawl, and also movable into and out of engagement with said toot-hed element, apertured lugs rigidly secured to the respective pawls, a bar slidably mounted in said lugs, stops carried by said bar, and springs coiled about said bar and cooperating with said stops and said lugs to control the positions of said pawls with rclat-ion to said toothed element.

5.. lln a lifting device, a toothed element, a pawl supporting member, a lifting pawl carried by said supporting member and movable into and out of engagen'ient with said toothed element, means for actuating said supporting member to impart bodily movement to said lifting pawl, a detent pawl mounted independently of said lifting pawl and also movable Vinto andout of engagement with said toothed element, apertured lugs rigidly secured to the respective pawls, a bar slidably mounted in said lugs, a stop carried by said bar between the ends thereof, other stops carriedvby said bar near the respective ends thereof and spaced from said intermediate stop, and; springs coiled-about said bar and confined between said lugs and said stops to control the positions of said pawls with relationto said toothed element.

6. In a lifting device, a toothed element, a pawl supporting member`,a lifting pawl carried by said supporting member and movable into and out of engagement with said toothed element, means for actuating said supporting member to impart bodily movement to said lifting pawl, detcnt pa'i'vl mountedindependently of saidlifting pawl and also mov-v able into and out of engagement with said toothed element, apertured lugs carried by the respective pawls, a bar slidably mounted in said lugs, a stop carried by saidbar between the ends thereof, other stops carried by said bar near the respective ends thereof and spaced from said intermediate stop, springs coiled about said bar and confined between said lugs and said stops'to control thepositions of said pawls with relation to said toothed element, andmeans for locking said bar against upward movement.

7.111 a lifting device, a toothed element, a pawl supporting member, alifting pawl carried by said supporting member and movable into and out of engagement with said toothed element, means for actuating said supporting member to impart bodily movement to said lifting pawl, a detent pawl mounted indeoendentl* of said liftingn iawl and also movable into and out of engagement with said toothed element,apertured lugs carried by the respective pawls, a slidably mounted in said lugs, intermediate` stop carried by said bar and lying beneath the lug of said detent pawl, a second stop carried by the lower.

portion of said bar and lying beneath the lug for said lifting pawl, a third stop carried by said bar and spaced some distance above the lug for said detent pawl, a. spring confined between said intermediate stop and the lug for said lifting pawl, and a second spring confined between said third stop and the lug for said detent pawl.v

8. In a lifting device, atoothed element, a pawl supporting member, a lifting pawl carried by said supportinfr member and movable into and out of engagement with said toothed i element, means for actuating said supporting member to impart bodily movement to said lifting pawl, a detent p awl mounted independently of said lifting pawl and also movlable into and out of engagement with said toothed element, apertured lugs carried by the respective pawls, a bar slidably mounted in said lugs, an intermediate stop carried by said bar and lying beneath the lug of said detent pawl, a second stop carried by the lower portion of said bar and lying beneath the lug for said lifting pawl, a third stop carried by said bar and spaced some distance above the lug for said. detent pawl, a spring confined between said intermediate stop and the lug for said lifting pawl, a second spring confined between said third stop and the lug for said detent pawl, and means for moving said bar downwardly and retaining the same in its lower position, whereby said springs are compressed and caused to act upon the respective lugs to hold said pawls yieldably in engagement with said toothed element.

9. In a lifting device, a toothed element, a pawl supporting member, a lifting pawl earried by said supporting member and movable into and out of engagement with said toothed element, means for actuating said supporting member to impart bodily movement to said lifting pawl, a detent pawl moimted independently of said lifting pawl and also movable into and out of engagement with said toothed element, apertured lugs carried by the respective pawls, a bar slidably mounted in said lugs, an intermediate stop carried by said bar and lying beneath the lug of said detent pawl, a second stop carried by the lower portion of said bar and lying beneath the lug for said lifting pawl, a third stop 'carried by said bar and spaced some distance above the lug for said detent pawl, a spring confined between said intermediate stop and the lug for said lifting pawl, a second spring confined between said third stop and the lug for said detent pawl, a locking plate movably mounted and overlapping the upper end of said bar, and means for pressing said locking plate into engagement with the end of said -bar and retaining the same in engagement therewith.

l0. in a lifting device, a toothed element, a pawl supporting member, a lifting pawl carried by said supporting member and moyable into and out of engagement with said toothed element, means for actuating said supporting member to impart bodily movement to said lifting pawl, a detent pawl mounted independently of said lifting pawl and also movable into and out of engagement with said toothed element, apertured lugs carried by the respective pawls, a bar slidably mounted in said lugs, an intermediate stop carried by said bar and lying beneath the lug of said detent pawl, a second stop carried by the lower portion of said bar and lying beneath the for said lifting pawl, a third stop carried by said bar and spaced some distance above the lug for said detent pawl, a spring confined between said intermediate stop and the lug for said lifting pawl,

a second spring confined between said third stop and the lug for said detent pawl, a locking plate pivot-ally mounted and overlapping the upper end of said bar, a pivoted dog arranged to engage said plate and to press the same, and a handle operatively connected with said dog. i

11. ln a lifting device, a toothed element, a pawl supporting member, a lifting pawl carried by said supporting member and movable into and out of engagement with said toothed element, means for actuating said supporting member to impart bodily movement to said lifting pawl, a detent pawl mounted independently of said lifting pawl and also movable into andout of engagement with said toothed element, a controlling member supported by said pawls, and capable of longitudinal bodilymovement withv relation thereto, a stopV movable into a position to limit the movement of. said member with relation to said pawls, and springs confined between said member and the respective pawls.

ln testimony whereof, we afhx our signatures hereto.

ION V., K. HOTT. WALTER A. SPEAK.