US1109980A - Lifting-jack. - Google Patents

Description

W. H. FORREST.

LIPTING JACK.

APPLICATION FILED FEB, 10, 1913.

Pat-exited Sept. 8, 1914.

2 SHEETSSHEBT 1.

fTz/vewitor ZU 7257168868 WzM W. H. FORREST.

LIFTING JACK. APPLICATION FILED 1 33.10, 1912.

Patented Sept. 8, 1914.

2 SHEETS SHEET 2.

UNITED S QFFICE- WILLIAM H. FORREST, OF BOSTON, MASSACHUSETTS, AS SIGNOR, ."BY DIRECT AND MESNE ASSIGNMENTS, TO EXCEL JACK IVIFG. 00., A CORPORATION OF MAINE.

LlFTING-J'ACK.

Specification of Letters Patent.

Application filed February 10, 1913. Serial No. 747,260.

T all whom it may concern:

Be it known that I, VVILLIAM H. Fonnns'r, a citizen of the United States, residing at Dorchester, Boston, in the county of Suffolk and State of Massachusetts, have 1nvented new and useful Improvements n Lifting-Jacks, of which the following 18 a specification.

This invention relates to improvements in lifting jacks.

The object of the invention is to'provide a powerful, compact jack hav ng a rest adapted to be rapidly elevated in an absolutely straight line and to be lowered at a comparatively slower speed, both the upward and downward reciprocations of said rest be ng accomplished without binding or cramping and with substantially no variations in the power required to operate the same.

The invention consists in the combination and arrangement of parts whereby the above object and certain other 0b ects herelnafter appearing are attained, as set forth in the following specification and particularly pointed out in the claims. V

Referring to the drawings: Figure 1 1s a side elevation of a jack embodying my in vention, with portions of said jack removed and shown in section to more clearly illustrate the invention. 2 is sectional plan view of the jack illustra Fig. 1 taken on line 22 of said fig h'ig. 3 1s a section taken on line 1. Figs. 4 and 5 are detail views inthe parts in their several positions. 1

1g. 6 is a detail view of the pawl slide with a portion of the rest stem shown in connection therewith. Fig. 7 is a detail view illustrating a modified form of the lifting lever and slide.

Like numerals refer to like par s throughout the several views of the draw In the drawings, 10 is ba provided with a pair of mailers 1 one end thereof, and hm extending upwardly the ard being preferabh, section and provided ries of teeth 13. A be adjusted vertic standard 12 and to ous positions relat 15 pivoted at 16 to .rably pivoted at idard 12 tand- $11111 L'lii' to engage the teeth 11;. "The pm. if) is pro vided with a handle 17 by Int-11in; of which the upper end of said carrier. The stem 20 4 also has slidin engagement with aslide 23 which in turn 1s adapted to be moved vertically relatively to said carrier in guides 24 formed therein.

A lever 25 is pivoted upon a stud 26 mounted in the ears 27 formed on said carrier. This lever is preferably forked at 28 to straddle the ears 27 and the extremities of said forked end are segmentally formed and provided with series of teeth 29, 29 which engage racks 30, 30 formed at opposite sides of the slide 23, said racks protruding from the interior of the carrier 14 through slots 81, said slots being of a suflicient length to permit the necessary movement of the slide 23 with their extremities constituting stops to limit the movements of said slide. For convenience in handling, the lever 25 is formed in two parts 32 and 33, the part 33 constituting a handle which preferably fits into a socket 34 formed in said member 32, but may be removed therefrom when the jack is not in use or when it is desired to store the same. The member 33 is preferably bent at 35 to place the handle thereof in a more elevated position where it may be easily operated.

By the rocking of the lever 25, the slide will be reciprocated vertically in said carrier, and to impart the reciprocations of said slide to said rest 18 a pawl 36 is pivotally arranged between ears 3? formed on said slide and adapted to engage the teeth .21 formed upon the stem 20 of said rest. Sevoral reciprmations of the slide 20 are necessary to elevate the rest 18 to its highest :t. and '1 I) retain the same in its several tions or during the downward reciprocaiim: of the slide 23 to obtain a new purchase upon the stem 20 a stop pawl 38 is provided. ()Wiugj to the limited angular movements of the h m- 25 whereby several stroke thereof Patented Sept. 8, 1914.

are necessaryto elevate the rest-l8, theleverage will always remain substantially uniform.

The carrier 14 is hollowed out to provide a chamber 39 andin said chamber are located the slide 23 with its pawl'36 and the stop pawl 38, said stop pawl 38 being pivoted at 40 near the lower end of said chamber. Within this chamber are also located means which cooperate with said slide during its reciprocations to alternately disengagesaid pawl and said stop pawl from said teeth whereby said rest may be lowered tooth by tooth. This means preferably comprises a tripping plate 41 which is arranged to slide in a slot 42 extending transversely of the slide 23 inthe side wall of said carrier.

The tripping plate 41 is arranged to'be withdrawn out of operation during the movements of said slide 23 to elevate said rest and to be yieldingly held in said position by a spring 43. When it is desired to move said tripping plate into its operative position a lever 44 pivoted upon the stud 26 and connected by a link 45 to said tripping plate is rocked upon said stud in the direction of the arrow a from the position illustrated in Fig. 1 to that illustrated in Fig. 5, or until the stop 46 on said lever engages the underside of the link 45, said link and lever constituting a toggle which when straightened as in Fig. 5, positively retains said tripping plate in its operative position.

Extending laterally from the plate 41 is warm 47, and during the lateral movement of the tripping plate toward the right Figs. 1 and 5, said arm is'brought into contact with one end of a rocker arm 48 pivoted at 49 to a lever 50 which in'turn is pivoted at 51 to the stop pawl 38 and by the engaging of said arm 47 with the end of said rocker arm .the tendency will be either to rock said rocker arm upon its pivot 49 or when this is prevented said rocker arm will be moved bodily toward the right carrying with it its pivot 49 and by so doing the stop awl 38 will be rocked upon its pivot 40 an the upper end thereof disengaged fromthe teeth 21. The rocking of the pawl 38 however should disengage the same from the teeth 21 and should be so rocked only when the slide 23'is in its uppermost position and to insure the proper movement of said rocker arm at this time it is provided at its upper end with a lateral projecting member 52 having an inclined face 53. This inclined face is adapted to be engaged by a roll 54 mounted upon the pawl 36 which contacts with said face when in its uppermost position and forces said arm 52 toward the right from the position illustrated in Fig. 1 to that illustrated in Fig. 5, but as hereinbefore stated only when the arm 47 is in contact with the lower end of the lever 48, the spring 55 being provided to return said moaned rocker arm and'said pawl to their normal positions after either the roll 54 or the arm 47, or both, have been withdrawn from contact therewith.

The pawl 36 is yieldingly retained in contact with the teeth 21 by a spring 56 which is preferably coiled about the stud 57 constituting the support" for the roll '54, one end of said spring being secured to the pawl 36 whil the other end is secured to a lever 58 pivoted upon the stud 57 which engages at its outer end a cam face 59, preferably formed upon the inner edge of the lever 50. The lower end of said lever is extended beyond the pivot 57 and constitutes a lug 60,

said lug being arranged to enga e an in-' clin ed face 61 upon the tripping p ate 41.

As hereinbefore stated one of the features of the jack herein described is its compactness which to a certain extent is due to the arrangement of the several moving parts relatively to the standard 12. By reference to Fig. 1 it will be seen that the rest 18 is in its lowermost position and when in such a position projects only slightly above the upper end of the standard 12. This is accomplished by arranging the stem of said rest in the carrier 14 at one side of said stem and recessing the base at 62 to permit the same to be lowered'to its full extent, then by forking the lever 25 an equal pressure will be applied to the opposite sides of the slide 23 simultaneously.

The preferred method of constructing the extremities of the lever 25 is to provide the teeth, as illustrated in Figs. 1, 4 and 5, which engage the teeth of the racks 30. I do not wish to be limited to this construction as any arrangement which will operate-to reciprocate said slide vertically through the .oscillatory movements of the lever 25 may be used, such for instance, as I have shown in Fig. 7 which consists of pins 63 formed upon opposite sides of the slide 23' and these pins engaging slots 64 formed in the extremities of the lever 25. the device hereinbefore specifically described is as follows: The jack with the carrier and rest in the positions illustrated in Fig. l is wheeled beneath the object to be lifted. The carrier is then adjusted vertically on the stem 12 until the rest 18 engages the underside of said object. The lever 25 is then rocked upon its pivot 26 which causes the slide 23 to be lowered one or more teeth or into the position illustrated in Fig. 4, both the pawl 36 and the stop pawl 38 being at this time in contact with the teeth 21. The handle 33 is then depressed and this operation is repeated until the rest'has been elevated the desired distance.

After the work upon the object, in its elevated positio-i has been completed and it is desired to lower the same the handle 33 of the lever 25 is depressed carrying the slide 23 The general operation of meaeso to its uppermost position. The lever 44 is i then rocked upon the pivot 26 in the direction of the arrow a, thus moving the tripping plate ll from its position illustrated in Fig. l to that illustrated in Fig. 5 engaging the lower end of the rocker arm 48 and disengaging the upper end of the stop pawl 38 from the teeth 21. The slide 23 is then lowered by rocking the lever 25 a slight distance, that is, until the lug 60 engages the inclined face 61. By lowering said slide it will be seen that the roll 51 will be withdrawn from the inclined face 53, thus permitting the pawl 38 to return into engagement with the next successive tooth of the series of teeth 21, said stem having been gradually lowered by the lowering of the slide as it is at this time supported by the pawl 36. The downward movement of said rest will continue until said stop pawl engages said next successive tooth as stated, but immediately'prior to its engagement the pawl 36 will be disengaged from its respective tooth by the engagement of said lug 60 with the inclined face 61 and permit said rest to drop until stopped by said stop pawl 38. The slide 23 is again raised and the operation just described'repeated to lower said rest tooth by tooth until the same engages the upper face of the carrier 14, it being understood that the lowering of said rest tooth by tooth takes place while said handle is in its lowermost position or in such a position that a minimum pressure will be necessary to hold the same.

Having thus described my invention what I I claim and desire by Letters Patent to secure is: V

1. A lifting jack having, in combination, a standard, a carrier adjustable vertically relatively to said standard, a rest slidably arranged on said carrier, teeth on said rest, a lever pivoted on said carrier, a pawl operatively connected with said lever adapted to be moved thereby to engage the teeth on said rest and to elevate said rest several teeth at one stroke of said lever, a stop pawl adapted to hold said rest in the positions to which it is moved by said pawl, and normally inactive means adapted to be operated by a limited movement of said lever to alternately disengage said pawl and said stop pawl from said teeth, whereby said rest may be lowered tooth by tooth. 2. A lifting jack having, in combination, a carrier, a. slide adapted to be moved vertically relatively to said carrier, a rest, means to reciprocate said rest relatively tosaid carrier, including a forked lever pivoted on said carrier, segmental gears arranged at the extremities of said forked end of said lever, racks on, said slide adapted to engage said segmental gears respectively, teeth on said rest, and a pawl on said slide adapted to engage said teeth.

3. A lifting jack having, in combination, a carrier, a slide adapted to be moved vertically relatively to said carrier, a rest, a stem depending from said rest and engaging said carrier and said slide, teeth on said stem, a

lever adapted to reciprocate said slide, a pawl carried by said slide adapted to engage said teeth to elevate said rest during the upward reciprocations of said slide, a stop pawl on said carrier to engage said teeth and support said rest during the downward reciprocations of said, slide, means to yieldingly retain said pawl in contact with said teeth, a rocker arm pivotally connected with said stop pawl, a trippingplate adapted to rock said rocker arm and means carried by said pawl adapted to engage said tripping plate during the downward reciprocations of said slide and disengage said pawl from said teeth, said means also adapted to engage said rocker arm during the upward reciprocations of said slide and disengage said stop pawl from said teeth whereby said rest may belowered tooth by tooth.

4. A lifting jack having, in combination, a carrier, a slide adapted to be moved vertically relatively to said carrier, a rest, a stem depending from said rest having slidable engagement with said carrier, teeth on said stem, a lever adapted to reciprocate said slide, a pawl carried by said slide adapted to engage said teeth to elevate said rest during the upward reciprocations of said slide, a stop pawl on said carrier to engage said teeth and support said rest during the downward reciprocations of said slide, a rocker arm pivotally connected with said stop pawl, a tripping plate adapted to rock said rocker arm, means carried by said pawl adapted to engage said tripping plate during the down ward reciprocations of said slide to disengage said pawl from said teeth, said means also adapted to engage said rocker arm during the upward reciprocations of said slide to disengage said stop pawl from saidteeth, and means to move said tripping plate into its operative position.

5. A lifting jack having, in combination, a carrier, a slide adapted to be moved vertically relatively to said carrier, a rest, a stem depending from said rest having slidable engagement with said carrier, teeth on said stem, a lever adapted to reciprocate said slide, a pawl carried by said slide adapted to engage said teeth to elevate said rest during the upward reciprocations of said slide, a stop pawl on said carrier to engage said teeth and support said rest during the downward reciprocations of said slide, a rocker arm pivotally connected with said stop pawl, a tripping plate adapted to rock said rocker arm, means carried by said pawl adapted to engage said tripping plate during the downward reciprocations of said slide to disen gage said pawl from said teeth, said means also adapted to engage said rocker QI'IH during the upward reciprocations of said slide to disengage said stop pawl from said teeth, and means to move said tripping plate into its operative position and to lock the same therein.

6. A lifting jack having, in combination, a carrier, a slide adapted to be moved verti- Cally relatively to said carrier, a rest, astem depending from said rest having slidable engagement with said carrier, teeth on said stem, a lever adapted to reciprocate said slide, a pawl carried by said slide adapted to engage said teeth to elevate said rest dur ing the downward reciprocations of said slide, a rocker arm pivotally connected with said step pawl, a tripping plate adapted to rock said rocker arm, means carried by said pawl adapted to engagevsaid tripping plate during the downward reciprocations of said slide to disengage said pawl from said teeth, said means also adapted to engage said rocker arm during the upward reciprocations of said slide to disengage said stop pawl from said teeth, and a toggle adapted to move tripping plate into its operative position and to look the same therein.

7 A lifting jack having, in combination,

a carrier, a slide adapted to be moved vertically relatively to said carrier, a rest, a stem teeth and support said rest during the downward reciprocations of said slide, a rocker arm pivotally connected with said stop pawl, a tripping plate adapted to rock said rocker arm, means carried by said pawl adapted to engage said tripping plate during the downward reciprocations of said slide to disengage said pawl from said teeth, said means also adapted to engage said rocker arm during the upward reciprocations of said slide to disengage said stop pawl from said teeth, a toggle adapted to move said tripping plate into its operative position and lock the same therein, and a spring adapted to return said tripping plate to its inoperative position when released by said toggle.

In testimony whereof I have hereunto set my hand in presence of two subscribing wit- VVlLLIAM H. FORREST. Witnesses FRANKLIN E. Low, SYDNEY E. TAFT.

, DGSSQS.

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