US1543486A - Positive stop for lifting jacks - Google Patents

Description

.h me 23, 1925 7 1,543,486

c. w. RIPSCH ET AL POSITIVE STOP FOR LIFTING JACKS Filed June 5, 1921 2 Sheets-Sheet l INVENTORS CMwaLtxw/F/Psnaf. Jvntsc rnwzcyg ATTORNEY June 23', 1925. 1,543,486

c. w. RIPSCH ET AL POSITIVE STOP FOR LIFTING JACKS Filed June 25, 1921 2 Sheets-Sheet 2 INVENTORS cur/met: w 19/1,!- .Jint; 61

ATTORNEY Patented June 23, 1925.

UNITED STATES PATENT OFFICE.

CHARLES WILLIAM RIPSOI-I AND JAMES C. DAVVLEY, OF DAYTON, OHIO, ASSIGNORS TO JOYCE-CRIDLAND COMPANY, OF DAYTON, OHIO, A CORPORATION OF OHIO.

POSITIVE STOP FOR LIFTING JACKS.

Applicatien filed June 25, 1921. Serial No. 480,302.

To, all whom it may concern..-

Be it known that we, CHAnLEs W. Rirsorr and Jaime C. DAWLEY, citizens of the United States, residin at Dayton, in the county of Montgomery and State of Ohio, have invented certain new and useful 1m: proveinents in Positive Stops for Lifting Jacks, of which the following is aspecification, reference being had therein to the accompanying drawing.

This invention relates to lifting jacks and the like, and more particularly to means for positively limiting the upward, movement of the lifting element of a lifting jack or the like. i

One object of the invention is to provide a simple, effective means for preventing an excessive upward movement from being imparted to the lifting element, thereby preventing accidents and the breakage of the mechanism. 1 V v A further object of the invention is to provide means for causing the lifting element to be automatically lowered when it has been elevated to a, predetermined height and for checking this downward movement when the lifting element has reached a posi tion below said predetermined height.

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

In the accompanying drawings Fig. 1 1s a vertical sectional view of a jack embodying our invention, taken on the line ll of Fig. 2; Fig. 2 is a transverse sectional view taken on the line 22 of. Fig. 1; Fig. 3 is a detail View of the controlling device; and Fig. at is a detail view of the actuating member forthe controlling device.

In these drawings we have illustrated one embodiment of our invention and have shown the same as applied to a self l0wer ing jack of the type shown and. described in Patent No. 1,3 9,101, granted to us August 10, 1920, but it will be'understood that the invention is not limited to jacks of this type but may be employed in jacks or lifting devices of various kinds.

I -The jack here illustrated is a high pow.- ered jack having a capacity of seventy-five tons and it comprises a base 1 hi-iving an upwardly extending hollow standard 2. ixed in the upper end of the hollow standard is a nut 3 in which is journaled a screw threaded shank 4 of a. lifting el ment The lifting element isprovided at its upper end with a load engaging member, or cap, 6, which is rotatable relatively thereto'and, in the present instance, is provided with a ball bearing 7 interposed between the lower surface of the cap andv the flat upper surface of the beveled gear 8 carried by the lifting element. Secured to thecap Grand extending about the standard 2 of the base is a housing 9, the lower portion of which engages the outer surface 'of the standard and serves to guide the lifting element in its vertical movement. The lifting element is actuated by means of the beveled gear 8 which is rigidly secured thereto and which meshes with a beveledgear 10 mounted on a shaft 11 journaled in the housing 9. As here shown, the housing 9 has secured to one side thereof a gear case comprising an inner wall 12, which closes an opening in the side of the housing 9 and thus forms a part of said housing, and an outer wallor casing 13. The shaft 11 of the gear 10 is journaled at. its inner end in a bracket let carried by the housing 9 and has its outer portion journaled in bearings formed in the walls 12 and 13.0f the gear casing. Rigidly secured to the shaft 11 within the gear casing is a gear 15 which meshes with a gear 16 secured to a shaft 19 also journaled in the walls 12 and 13 and projecting beyond the wall 13 to receive an actuating device.

This actuating device is here shown as a ratchet 20 with which cooperates a lever 21 carrying the pawl (not shown). The pitch of the thread on the shank 4- 0f the lifting element is such that under a normal load the lifting element will move downwardly by gravity and means are provided for controlling this downward movement. In-the particular ack here shown a worm wheel 22 is loosely mounted on the shaft 19.,and is adapted to be connected therewith, when thelifting element moves downwardly, by a clutch 23, so that the worm gear will rotate only when the lifting .element is moved downwardly. The worm.wheel-22 meshes with a worm 24 mounted on a shaft 25 and the Worm and worm gear have their spirals arranged ,at such a pitch that theworm will be driven by the worm wheel. Rigidly secured to the shaft 25 is a second worm wheel 26 which meshes with a worm 27, the spirals of this worm and Worm wheel also being such that the worm wheel will drive lifting element.

the worm. A controlling device is applied to the worm 27 to control the downward movement of the load and in the present instance this controlling device comprises a brake consisting of a drum 28 rigidly secured to the reduced portion of the worm 27. Cooperating with this brake drum is a friction device, such as a pair of friction shoes 30 which are pivotally mounted at one side of the drum and provided on the other side of the drum with arms 31 which are acted upon by a spring 32 to move the shoes into frictional contact with the drum and thus hold the latter against rotation. To permit the load to move downwardly the arms 31 are separated against the tension ofthe spring and, as here shown, a stud 33 is mounted in the wall of the gear casing and has its inner portion extending between the two arms and flattened so that when the stud is rotated the flattened portion thereof will engage the arms with a cam action and separate the same. The outer end of the stud 33 extends beyond the wall of the housing and has secured thereto an actuating lever 34 by means of which the stud may be actuated and the movement of the load controlled.

It will be apparent from the foregoing description that the brake is normally set and will prevent the downward movement of the load in the intervals between the operation of the lever which actuates the To preventthe lifting element from being elevated above a pre determined height we have provided means for automatically actuating the controlling device to release the lifting element and permit the latter to move downwardly. Consequently, when the lifting element reaches this predetermined height it will be released and will move downwardly as soon as the pressure on the operating lever for the lifting element is relieved, and any further operation of the lever would merely result in the load being moved up and'down without the possibility of any undue pressure being applied to any part of the mechanism which might result in breakage or of other accidents due to the excessive movement of the lifting element. To so actuate the controlling device, the standard and the con trolling device are provided with cooperating parts which are brought into operative relation just before the lifting element reaches the prescribed limit of its movement, so that the further movement of the lifting element will cause the controlling device to be actuated.

In the particular embodiment of the in vention here illustrated we have secured to the actuating lever 34 for the controlling device, a projection, or finger, 35 which extends through a slot 36 in the wall of the housing andlias connected therewith a part,

adapted to engage a fixed stop carried by the standard. In the present instance, we have connected with the projection, or finger, 35 a rod 37 which is mounted in a channel v38 formed in the wall of the housing 9, and has secured thereto a stop 39 which, when the lifting element and housing have been moved upwardly a predetermined distance, will engage a fixed stop on the standard. The fixed step may be of any suitable character but inasmuch as the housing which carries the operating mechanism for the jack is ro-tatably mounted on the standard it will be apparent that the jack may be operated with the movable stop 39 adjacent to any part of the standard. It is, therefore, desirable that the fixed stop be of such a character that it will cooperate with the movable stop in any position occupied by the latter. We have, therefore, shown the fixed stop as annular in form, and, in the present construction it comprises a flange 40 carried by the nut 3 and overlapping the edge of the standard and the channel 38 in the housing. Consequently, any movement of the lifting element beyond the prescribed limit will bring the stops into engagement thus checking the movement of the rod 37 and permitting the housing, and the controlling device, which is carried thereby, to move relatively to the rod, thereby causing the actuating lever 34 to be operated to release the brake. As soon as the lifting element has moved downwardly far enough to relieve the pressure on the rod 37 the brake will again be set, by the action of the spring 32, and the further downwardmovement of the lifting element prevented. V

The stop 39 is preferably adjustable on the rod 37 so that the height at which the movement of the lifting element will be interrupted may be regulated. As here shown, the stop 39 is in the form of a. nut screw threaded onto the lower end of the rod 37 and held in adjusted positions by means of a am nut 41. A spring 42 acts on the stop 39 to counter balance the weight of the stop and the rod so that normally these will not interfere with, or have a tendency to cause the operation of, the actuating lever 34 for the controlling device. Consequently, at all times except when the stop 39 is in engagement with the fixed stop on the standard the controlling device may be manipulated in the usual manner. The wall of the housing 9 is provided with an opening, normally closed by a screw threaded cap 43, to permit access to the channel 38 and the rod and stop.

The lifting element of the jack will move downward by gravity only when under asubstantial load and, consequently, if the jack is run up without load the release of the brake will not operate to check the movement of the lifting element. We have, there fore, provided other means for positively limiting themovement of the lifting element when the jack is operated without load and, as here shown, a flange 40 is secured to the nut 3, or if desired to the standard 2, and extends beyond the edge of the standard and into the path of ashoulder 45 formed near the lower end of the housing 9 so that when the lifting element reaches the upper limit of its movement the shoulder 45 will engage the flange 44 and prevent the further movement of the lifting element. hen the jack is operated under a heavy load the power required to elevate the load is so great that if a rigid stop,'such as the parts 45 and 40, is employed it frequently happens that the operator will not know when the stops have come into engagement and will continue to apply power to the jack, which may result in breakage or damage of some kind, but when the jack is operated without load only a small amount of power is required to elevate the lifting element and the operator will know instantly when the rigid stops contact one with the other and will discontinue the application of power thereto. It will be noted that the stops 39 and 40 are so arranged that they will cause the operation of the controlling device before the stops 40 and 45 come into engagement. Consequently, if the jack is operated under load the stops 40 and 45 need not come in contact. It will also be noted that the stops 40and 45 are of such a character that they will not only limit the upward movement of the lifting element relatively to the standard but will prevent the standard from running out of the housing and becoming separated from the lifting element in the event of the jack being lifted above the ground.

The operation of the device will be readily understoodfrom the foregoing description and it will be apparent that we have provided a very simple and highly efiicient means for positively preventing the movement of the lifting element above a predetermined height and while we have shown and described one embodiment of our invention we wish it to be understood that we do not desire to be limited to the details thereof as various modifications may occur to a person skilled in the art.

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

1. In a lifting jack, a lifting element, actuating means for said lifting element, means to control the downward movement of said lifting element, and means to automatically operate said controlling means when said lifting element has been elevated to a predetermined height and thus permit said lifting element to move downwardly.

2. In a lifting jack, a lifting element, actuating means for elevating said lifting element, a controlling device operating normally to prevent the downward movement of said lifting element, and means to automatically render said cont-rolling device inoperative when said lifting element has been elevated to a predetermined height.

3. In a lifting jack, a lifting element, actuating means for elevating said lifting element, a brake operating normally to prevent the downward movement of said lifting element, and means to automatically actuate said brake to release said lifting element when the latter has been elevated to a pre-' determined height. 4. In a lifting jack, a lifting element, actuating means for said lifting element, a friction drum so connected with said lifting element that it will be rotated by the downward movement thereof, a friction element cooperating with said drum, a spring to hold said friction element in operative engagement with said drum, and means to automatically release said drum when said lifting element has been'moved to a predetermined height.

, 5. In a lifting jack, a lifting element,

actuating means for said lifting element, a controlling device operating normally to prevent the downward movement of said lifting element, means controlled by the movement of said lifting element for actuating said controlling device to release said lifting element for downward movement when said lifting element has been elevated 4 to a. predetermined height, and to interrupt said downward movementwhen'the lifting element has moved toa position below said predetermined height. v

6. In alifting jack, 'a standard, a lifting element movably mounted on said standard, means for imparting lifting movement to said lifting element, a device to control the downward movement of said lifting element. and means controlled by the movement of said lifting element'relatively to said standard to actuate said controlling device.

7. Ina lifting jack, a standard, a lifting element movably mounted on said standard, means for imparting movement to said lifting element. a device to control the downward movement of said lifting element, and cooperating parts carried by said standard and said lifting element to actuate said controlling device.

8. In a lifting jack, a standard, a lifting element movably mounted on said standard, a device carried by one of said parts to control the downward movement of said lifting element, means carried by the other of said parts to cause said device to be actuated, and means to impart lifting movement to said lifting element.

9. In a lifting jack, a standard, a lifting element movably mounted on said standard, means for imparting lifting movement to said lifting element, a device carried by and. movable with said lifting element to control the downward movement thereof, and means carried by said standard to cause the operation of saidcontrolling device.

10. In a lifting jack, a standard, a lifting element movably mounted on said standard, means for imparting lifting movement to said lifting element, a device carried by and movable with said lifting element to control the downward movement thereof, and means mounted on a relatively Xed part to cause the operation of said. controlling device.

11. In a lifting ack, a standard, a lifting element movably mounted on said standard, means for imparting lifting movement to said lifting element. a device carried by and movable with said lifting element to control the downward movement thereof, and comprising an actuating member, and a part carried by said standard and arranged to impart movement to said actuating member.

12. In a lifting 'ack, a standard, a lifting element movably mounted on said standard, means for imparting lifting movement to said lifting element. a device carried by and movable with said lifting element to control the downward movement thereof, and comprising an actuating member, a stop carried by said actuating member, and a second stop carried by said standard and arranged in the path of the stop carried by said actuating member.

13. In a lifting jack, astandard, a liftin element movably mounted on said standard. means for imparting lifting movement to said lifting element, a device carried by and movable with said lifting element to control the downward movement thereof, and comprising an actuating member, a stop adjustably connected with said actuating member and a part carried by said standard and arranged to be engaged by said stop to impart movement to said actuating member.

1 1-. In a lifting jack, a standard, a lifting element movably mounted on said standard, means for imparting lifting movement to said lifting element, a device carried by and movable with said lifting element to control the downward movement thereof, and comprising an actuating member. a rod connected with said actuating member and extending lengthwise of said standard, a stop carried by said rod, and a stop carried by said standard and arranged in the path of the first mentioned stop.

15. In a lifting jack, a standard, a lifting element movably mounted on said standard, means for imparting lifting movement to said lifting element, a device carried by and movable with said lifting element to control the downward movement thereof, and comprising an actuating member, a rod connected with said actuating member and extend ing lengthwise of said standard, a stop adjustably mounted on said rod, and a part carried by said standard and arranged in the path of said stop.

16. In a lifting jack, a standard, a lifting element movably mounted on said standard,

means for imparting lifting movement to said lifting element, a device carried by and movable with said lifting element to control the downward movement. thereof, andcomprising an actuating device, a part oper atively connected with said actuating device, a part carried by said standard and arranged to cause the operation of the first mentioned part, and means to counter balance said first mentioned part and to retain said actuating device in its normal position.

17. In a lifting jack, a standard, a lifting element movably mounted on said standard, means for imparting lifting movement to said lifting element, a device carried by and movable with said lifting element to control the downward movement thereof, and comprising an actuating member, a rod connected with said actuating member, a stop mounted on said rod, a second stop carried by said standardand arranged in the path of the first mentioned stop, and a spring acting on said first mentioned stop to cause said actuating member to be supported in its normal position. I

, 18. In a lifting jack, a standard, a lifting element mounted in said. standard, means for imparting lifting movement to said lifting element, a housing carried by said lifting element and embracing said standard, a device carried by said housing to control the downward movement of said lifting element, said device having an actuating lever, said housing having a channel arranged alongside of and extending lengthwise of said standard, a rod connected with said actuating lever and arranged in saidchannel, a stop mounted on said rod, and a part carried by said standard and arranged in the path of saidstop.

19. In a lifting jack, a standard, a lifting element movably mounted on said standard, means for imparting lifting movementto said lifting element, a device for controlling the downward movement of said lifting element, said device being movable about said standard and comprising an actuating member, and a part extending about said standard and arranged to impart movement to said actuating member when said lifting element has been moved to a predetermined position.

20. In a lifting jack, a standard, a lifting element movably mounted on said standard, means for imparting lifting movement to said lifting element, a device carried by and movable with said lifting element to control the downward movement thereof, said device being rotatable aboutsaid standard and comprising an actuating member, a stop carried by said actuating member, and a second stop carried by and extending circumferentially of said standard and so arranged that it will be engaged by the first mentioned stop when said lifting element has been elevated to a predetermined height.

21. In a lifting jack, a standard, a lifting element movably mounted on said standard, means for imparting lifting movement to said lifting element, a device carried by and movable with said lifting element to control the downward movement thereof, said device being rotatable about said standard and comprising an actuating member, a stop carried by said actuating member, and an annular flange mounted at the upper end of said standard and extending laterally beyond the same into the path of the first mentioned stop.

22. In a lifting ack, a standard, a lifting element movably mounted on said standard and arranged to move downwardly by gravity when under'load, means for imparting lifting movement to said lifting element, a device carried by and movable with said lifting element to control the downward movement thereof, means to automatically actuate said controlling device to release said lifting element for downward movement when it has been elevated to a predetermined height, and other means for interrupting the upward movement of said lifting element at a predetermined height when said jack is operated without load.

23. In a lifting jack, a standard, a lifting element movably mounted on said standard and arranged to move downwardly by gravity when under load, means for imparting lifting movement to said lifting element, a device carried by and movable with said lifting element to control the downward movement thereof, means to automatically actuate said controlling device to release said lifting element for downward movement when it has been elevated to a predetermined height, a stop carried by said standard, and a second stop connected with said lifting element and arranged to engage the first mentioned stop when said lifting element has been elevated to a predetermined height.

24. In a lifting jack, a standard, a lifting element movably mounted on said standard and arranged to move downwardly by gravity when under load, a housing carried by said lifting element and embracing said standard, means carried by said housing for imparting movement to said lifting element, a device carried by said housing to control the downward movement of said lifting element, means to automatically operate said controlling device to release said lifting element for downward movement when it has been elevatedto a predetermined height, a flange secured to said standard at the upper end thereof and extending laterally beyond said standard, and a stop carried by said housing and arranged to engage said flange when said lifting element has been moved to a predetermined height.

25. In a lifting jack, a lifting element, means to actuate said lifting element, an, operable device carried by said lifting element to control the movement thereof, and actuatingmeans for said device controlled by the movement of said lifting element.

In a lifting jack, a non-rotatable nut, a lifting screw mounted in said nut, means to actuate said lifting screw, a controlling device which will normally permit the upward movement of said lifting screw, and means controlled bv the movement of said lifting screw and acting on said controlling device to cause it to prevent further upward movement of said lifting screw.

In testimony whereof we aflix our signatures hereto.

CHARLES WILLIAM RIPSCH. JAMES C. DAVVLEY.

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