US1163169A - Brake mechanism for hoisting apparatus. - Google Patents

Description

E. PAVELKA.

BRAKE MECHANISM FOR HOISTING APPARATUS.

APPLICATION FILED AUG.25. 1914.

1,163,169. Patented Dec. 7, 1915.

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Specification of Letters Patent.

Patented Dec. "Z, 1915.

Application filed August 25, 1914. Serial No. 858,452.

To all whom it may concern:

Be it known. that I, EDWARD PAVELKA, a

. citizen of the United States, residing in the specification.

:The invention relates to hand operated hoisting apparatus designed for lifting comparatively light loads, and is based upon Letters Patent to John A. Kearney, dated 1 May 19, 1914, No. 1,097,233.

The object of the invention is to provide means for reliably locking the drive-shaft while the load is controlled by the brake a larger scale.

alone and thus prevent the accidental reengagement of the drive-shaft with the winding-shaft and eliminate the danger of idle revolutions of the crank during the lowering operation.

Another object is to provide simple means conveniently located for holding the drive shaft in engagement with the winding-shaft and preventing accidental release during the hoisting operation.

The invention consists in certain details of construction and arrangement by which the above objects are attained, to be hereinafter described and claimed;

The accompanying drawings form a part of this specification and show the invention as it has been carried out in practice.

Figure 1 is a side elevation of'the improved hoisting apparatus and a portion of the telescopic standard on which it is mounted. Fig. 2 is a plan view of the mechanism on Fig. 3 is a corresponding side elevation of a portion, partly in vertical section, the plane of section being indicated by the broken line 33 in Fig. 2.

Fig. 4 is anelevation of portion showing the locking means, certain parts being in vertical section. Fig. 5 1s a front view of the locking tooth alone, on a still larger scale.

Similar letters of reference indicate the same parts in all the figures.

A is a standard supporting a head B mounted upon the upper end thereof and forming part of an overhanging frame having two outwardly extended arms B B in which are mounted two parallel horizontal shafts C and D, the former a relatively fixed windingshaft carried at the outer ends of the arms, and the latter an axially slidable drive-shaft -mounted between the winding shaft and head B. On the winding-shaft C isa gearwheelC a winding-drum or spool C on which the hoisting cable M is wound, and a brake-drum C all fixed on the shaft C and revolving therewith. llhe drive-shaft D carries a pinion D fixed thereon adapted to mesh -with the gearwheel G and is squared at one end a. receive the crank F by which it may be revolved and correspondingly rotate thewinding-shaft. The shaft D ismounted toslide axially under certain conditions and is extended out: wardly at the end opposite to the crank to permit such endwise movement without escaping from its bearings in the arms B B Partially encircling the brake-drum is a brake-band E attached to a brake-lever G in such manner as to tighten the band when the lever is raised and thus grasp the brakedrum. Fixed on the shaft D is a cone D lying normally adjacent to the brake-lever G which has an arm G extending beneath the cone to ahigh point on the latter, and as the lever is raised to applythe brake the arm G acts onthe inclined surface of the ,cone and forces the latter with the shaft D to. move axially thussliding the teeth of the pinion D on those of the gearwheel C while still in mesh therewith until at the point at which the brake friction is sufficient to hold the load, the teeth of the pinion are disengaged completely from the gearwheel and the suspended load is held by the brake alone; In this condition the load may be mounted on the frame at h and adapted to ride the teeth of the pinion B when the 'latter is rotated in the direction to hoist,

and to engage theteethand hold the pinion against rotation in the direction to lower.

The nose of the pawl is of such width as to maintain its engagement with the pinion even when the latter is moved axially out of mesh as above described.

To insure against accidental or unintengrOQVQ d in such shaft.

tional endwise movement of theshaft during the hoisting operation a latch J 1s provided, pivoted on the exterior of the arm B at y and having a curved arm J partially encircling the shaft and having a portion J 2 adapted to engage in an annular The latch is conveniently located adjacent the brake-lever G and is raised to free the shaft before the application of the brake by depressing the thumb-plate J 3 thereon, and the lifting movement is limited by the tailJ striking the head of the bolt G on which the brakelever is pivoted, thus holding the latch supported idly on the end of the shaft 'D during the shifting movement and in position to fall by gravity into engagement with the groove cl when the latter is again presented thereto.

It has been found desirable to provide means for preventing the partial rengage- 'ment of the pinion and gearwheel during the lowering operation in order to avoid danger to the operator by the accidental revolutions of the crank F liable to be thus induced. For this purpose a pin or tooth L is secured to the inner face of the arm 13 in position to be engagedbetween ad jacent teeth on the pinion D when the latter and its shaft'D are moved axially to disengage the pinion and gearwheel, and thus- 7 lock the shaft D against rotation "in either rotation'until such movement is completed and the load held by the brake. When the direction. The tooth L is shaped to match the space between adjacent teeth on the pin ion and'ex'tends close to the side face of the latter so that its engagement follows immediately upon the endwise movement of the shaft, and the mechanism is locked against pinion is freed from the gearwheel it is still locked and the drive-shaft and crank held against rotation until the reengagement of the'pinion and gearwheel is againfully established ready for another hoisting operation. The tooth L is shown as having a base L secured to the inner face of the arm B but it will be understood it may be otherwise shaped and located. The form of the latch J may be varied and any suitable stop supplied therefor in'place of the bolt G I I claim I 1. In a hoisting apparatus, a windingshaft, a gearwheel and winding-drum fixed thereon, a brake device on said shaft, a lever for operating such brake device, an axially I slidable drive-shaft, a pinion fixed on said drive-shaft and arranged to mesh with said gearwheel, a cone fixed on said drive-shaft,

and means carried by said lever for engag ing said cone and moving said drive-shaft axially, thereby sliding said pinion out of mesh with said gearwheel in the act of applying the brake,"andfixed means arranged to engage said pinion immediately after the initiation of such axial movement and hold said pinion and drive-shaft against rotation.

2. In a hoisting apparatus, a winding shaft, a gearwheeland winding-drumfixed thereon, a brake device on said shaft, a

. tiation of such axial movement and hold said pinion and drive-shaft against rotation.

3. In a hoisting apparatus, a windingshaft, a gearwheel and winding-drumfixed thereon, a brake device on said shaft, a

lever for operating such brake device, an.

axially slidable drive-shaft having an annu lar groove therein, a pinion fixed on said drive-shaft and arranged to mesh with said gearwheel, a cone fixed on said drive-shaft,

and means-carried by said lever for engaging said cone'and moving said drive-shaft axially, thereby sliding said pinion out of mesh with said gearwheel in the act of applying the brake, a tooth fixedly mounted relatively. to said pinion and arranged to be received between adjacent gear teeth. on

direction of the length of its shaft and a latch arranged to engage such groove and hold said drive-shaft against such axial movement until released.

4. In a ho1st1ng apparatus, a frame having outwardly extending arms, a windingshaft mounted'in saidarms, a gearwheel and winding-drum fixed on said winding-shaft, a brake device on said winding-shaft, a brake-lever on one of said arms for operatingsaid brake device, an axially slidable drive-shaft mounted in said arms and having an annular groove in one end exterior to one of said arms, a pinion fixed on said drive-shaft and arranged to mesh with said gearwheel, a cone fixed on said drive-shaft,

and means carried by said lever forengaging said cone and moving said drive-shaft axially, thereby sliding said pinion out of mesh with said gearwheel in the'act of applying. the brake fixed means engageable with said pinion to hold the same against rotation, and means to hold said pinion from sliding out of engagement with said means.

.5. In a hoisting apparatus, a frame having outwardly extending arms, a windingshaft mounted in said arms, a gearwheel and winding-drum fixed on said winding-shaft a brake device on said winding-shaft, a

"said pinion as the latter. is moved in the brake-lever on one of said arms for operating said brake device, an axially slidable drive-shaft mounted in said arms and having an annular groove in one end exterior to one of said arms, a pinion fixed on said drive-shaft and arranged to mesh With said gearWheel, a cone fixed on said drive-shaft, and means carried by said lever for engaging said cone and moving said drive-shaft axially, thereby sliding said pinion out of mesh with said gear-Wheel in the act of applying the brake, a latch pivotally mounted on one of said arms and arranged to fall by gravity into engagement With such groove and hold said drive-shaft against such axial movement, means for limiting the lifting release movement of said latch, and fixed means on the other of said arms to be received between adjacent teeth on said pinion as the latter is moved in the direction of the length of its shaft.

In testimony that I claim the invention above set forth I afiix my signature, in presence of two Witnesses.

EDWARD PAVELKA.

Witnesses: 7

CHARLES R. SEARLE, SOPHIE KEITEL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G.

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