US1234334A

US1234334A - Brake mechanism for lifting-jacks.

Info

Publication number: US1234334A
Application number: US15207117A
Authority: US
Inventors: Isaiah E Hindman
Original assignee: DUFF Manufacturing CO
Current assignee: DUFF Manufacturing CO
Priority date: 1917-03-02
Filing date: 1917-03-02
Publication date: 1917-07-24
Anticipated expiration: 1934-07-24

Description

I. E. HZNMAN.

BRAKE WICHANIS FOR LIFTMG lACKS.

APPLICATION mm MAR. 2. um

SP6 k WITNESSES INVENTOR a fhg y (mfl mum (MAM E( @xiii (Q /MCM l@ Q 2x Q Patented my um.

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][STL' E. HINDMAN, OF GRAFTON, PENNSYLVANIA, ASSG-NOE, TO THE JDUFF MANU- FACTUMING- COMPANY, OlE PITTSBURGH, PENNSYLVANIA, A CORPORATION OF IPENNSYLVANLVM.

To all whom t mail concern,

Be it lmown that l, daarin E. lli-noemer, a citizen of the `United States, residing at Grafton, in the county of Allegheny and State of Pennsylvania, have invented a new and useful llinprovement in Brake Mechanisin for Lifting-Jacks, of which the followin is a full, clear, and enact description., reierence being had to the accompanying drawin s, :torming part oi this specification, in whic t lligure 1 is a sectional view, partly broken away, oi a lifting jack embodying iny invention.

hig. 2 is a detail view, partly in end elevation and partly in vertical section showing the manually controlled brake device.

My invention has relation to brake mechanism for load raising and lowering apparatus, and is more particularly applicable-to lifting jacks et the class known as high speed screw jacks. rihe invention is further particularly applicable to that type of high speed screw jack known as the self rundown jacks, in which. the angle of the thread of the main lifting screw is Sadi-- cientl great to permit the load to torce the jack own after it has been raised.

My invention is designed to provide a brake mechanism ier a jack oi this character by means oi." which both the speed and the extent of the lowering may be perfectly controlled without jarring or injury to the jack, its load, or its support, under manimum loads.

l accomplish this object by the provision of an auxiliary train of gears which is 'idle during the raising movement of the jack and which is arranged to be brought into action during the lowering movement; and also by the provision and connection with the auxiliary gears oiI a load operated automatic brake device. li also preferably provide in connection therewith a manually operated brake deviceg ldy invention will be best understood by reference to the accompanying drawing, in which l have shown the preferred embodiment thereof* and which will now be described, it being premised, however, that various changes can be made in the details oit construction and arrangement of the s everal parts, without departing from the spirit specification of Lettera Eatent.

:HEME 'MECHNSM FOR LIFTIil'G-JACKS.' v

Patented duly 2d, ildilt.

Application flied March 2, 191th aerial 1t' o; 152,021.

and scope of my invention, as dened in the appended claims.

lin the drawings, the numeral 2 designates a suitable base supporting'the standard 3, and fl designates the housing of the jack provided with a sleeve portion 5, which has a sliding it with the standard 6 is the top or load sup orting plate carried by the housing 4l, and is the main lifting screw. 'lhis screw may be actuated by any suitable or usual mechanism to raise the load. in the drawing l have indicated a beveled pinion 8 carried by a shaft 9, which may be actuated in any usual or 'suitable manner, the pinion meshing with the beveled gear wheel 10 rigidly fixed to the upper portion of the screw 7.

11 designates a spur gear wheel which is also xed to the upper portion of the screw 7 above the gear wheel 10 and which meshes with the spur pinion 12 on a vertical shaft 13. This shaft 13 has a single actingclutch la by which it is connectedto a beveled gear wheel 15 meshing with another beveled gear wheel 16 which drives a train of multiplying gears 1'?. rlhe last wheel 17a of this train is a worm wheel, and has its teeth in mesh with a worin 18 on a transverse brake shaft 19 journaled'in the housing 4.

20 is a brake disk which is slidably mounted on the shaft-,19 for movement toward and away from the iXed abutment 21 (which may be formed as a part ot the housing fi). rThis brake disk and the adjacent face of the abutment 21 are provided with suitable cooperating lfriction surfaces. Connected to the sleeve or hub portion 22 of the brake disk are jointed links 23 which carry the governor balls 24:, the links being connected at their opposite ends to the collar 25 fixed to the shaft 19.

26 is a brake wheel which is also fixed to the shaft 19 and which is engaged by pivoted jaws 27, which are pressed against the wheel 26 by the action of a spring 28. These jaws may be separated to release their braking action by any suitable manually actuated device, such as the crank shaft 29 carrying the spreadingcam 30 between said jaws.

When the jack is being raised, the spur gears 11 and 12 are revolved, but the action of the clutch 14: is such as to leave the beveled gear and the train ot multiplying gearing idle. rfhe brake jaws 27 are pressing against the brake wheel 26, but as the clutch 14 is not operatively engaged, t h1s braking action does not retard the raising of the jack. As soon, however, as the raising effort is released, the reverse action of the main screw 7 and of the gears 10, 11 and 12 causes'the clutch 14 to become operatively engaged, thereby tending to revolve the auxiliary gears and the shaft 19. The brake jaws 27 are now fully operative and hold the load by preventing reverse movement of the screw 7. When self-lowering is required, the crank 29 is operated in a direction to release the brake jaws 27. The shaft now commences to revolve and as the speed increases the governor balls 2 4 fly outwardly, ythereby bringing the friction disk 20 into braking engagement with the abutment 21. 1n this manner, the speed of self-lowering may be automatically controlled so as not to become excessive, and the load can be stopped at any desired point at any time by again turning the crank 29 to permit the brake jaws 27 to again engage the brake wheel 26.

The advantages of'my invention will be readily understood since it provides a selflowering high speed screw jack which can be either held against lowering movement scribed, since it will be obvious that there.

are many devices of this character known in the arts which may be substituted for the particular forms thereof which 1 have herein shown and'r described. It will also be understood that the train of auxiliary gearing may be arranged `otherwise than as shown herein and that various struction and arrangement of the parts within the spirit and scope of the appended claims.

My invention may also be applied to other forms of load lifting apparatus.

l claim:

1. A load lifting apparatus having a main lifting screw with means for actuating the same, a train of auxiliary gearing, .a

single actingclutch connection between the' screw and the auxiliary gearing and arranged to operate the auxiliary gearing only when the screw is turning in a loadothery changes may be made in the details of. conlowering direction, and a brake shaft driven by said gearing, together with an automatic speed controlled braking device operated by said shaft and auxiliary gearing; substantially as described.

2. A load 'lifting apparatus having a main lifting screw with means for actuating the same, a train of auxiliary gearing, a single acting clutch connection between the screw and the auxiliary gearing and arranged to operate the auxiliary gearing only when the screw is turning in a load-lowering direction, a brake shaft driven by said gearing, a braking member carried by said shaft, coperating braking means normally engigingsaid member, and means for manna y releasing the cooperating braking means; substantially as described.

3. A load lifting apparatus having a main lifting screw with means for actuating the same, a train of auxiliary gearing, a single acting clutch connection between the screw and the auxiliary gearing and arranged to operate the auxiliary gearing only when the screw is turning in a load-lowering direction, a brake shaft driven by said caring, and an automatic'speed controlled raking device operated by said shaft and auxiliary gearing, said shaft also having a manually controlled braking device; substantially as described.

4. In a quick action self-lowering jack, the combination with a main screw, of an auxiliary train of gearing, a driving connection between the main screw and the train of gearing, said connection including a single acting clutch which is arranged to actuate said gearing only when the screw is turning in a load-lowering direction, a brake shaft havinga worm gear connection with said auxiliary train, and an automatic speed controlled brake device actuated by said shaft; substantially as described.

5. In a quick action self-lowering jack, the combination with a main screw, of an auxiliary train of gearing, a driving connection between the main screw and the train of gearing, said connection including a single acting clutch which is arranged to actuate said gearing only when the screw `is turning in a load-lowering direction, a

brake shaft having a worm gear connection with said auxiliary train, and an automatic speed controlled brake device actuated by said shaft, said shaft also having a manually controlled brake device; substantially as described.

6. 1n a quick action self-lowering jack, the combination with a main, load-lifting screw, of a train of auxiliary gearing having driving connection with said screw, said driving connection including a single acting clutch, and an automatic brake device actuated by said train of gearing; substantially as described.

7.111 a quick action self-lowering jack, with a hand controlled brake device also the combination With a main load-lifting arranged to act upon the screw through said screw, of a train of auxiliary gearing havgearing; substantially as described. 10 ing driving connection With said screw, said In testimony whereof I have hereunto set driving connection including a single acting my hand. clutch, and an automatic brake device actuated by said train vof gearing, together ISAIAH E. HINDMAN.