US1083412A

US1083412A - Electric hoist.

Info

Publication number: US1083412A
Application number: US592?6?10A
Authority: US
Inventors: Harry B Shreve
Original assignee: Weir & Craig Manufacturing Co
Current assignee: Weir & Craig Manufacturing Co
Publication date: 1914-01-06
Anticipated expiration: 1931-01-06

Description

H. B. SHREVE.

ELECTRIC HOIST.

APPLICATION FILED Nov.14, 1910.

Patented Jan. 6, 1914.

3 SHEETS-SHEET 1.

H. B. SHREVE.

ELECTRIC HOIST.

APPLICATION FILED Nov. 14, 1910.,

Ptented J an. 6, 1914.

3 SHEETS-SHEET 2.

. SHREVE.

ELECTRIC HOIST.

,APPLICATION FILED NOV; 14, 1910.

Patented Jan. 6, 1914.

3 SHEETS-SHEET 3.

V1 and 4.

hook 14, and the brushes are carried. by acircular boss 20 at the top of the casing section 3. The conductors are led from the brushes 18 outward through an aperture 1n Vthe side of the boss 20, with which there is connected a pipe 21, connected by a T with the pipe 22, connecting the casing sections The current distributing wiring is therefore on the outside of the casing proper, and is readily accessible for connection or disconnection at times when the casing sections are to be separated. For this purpose, connections are made at the respective boxes 23.with the controller and motor, in such manner as to be readily accessible through the covers of said boxes.

The motor is housed Within the ca sing section 4, and is represented in the drawings by said casing section, and such other arts as are visible in Fig. 4. rlhe end of the rotor shaft 24, which is toward the right in Fig. 4, has an axial socket, preferably of hexagonal or other fiat sided forni, for receiving the correspondingly formed end of.

the floating shaft 25. The righthand end of the shaft 25 is journaled in a bearing in the partition 26, which forms a removable end plate for the righthand end of the casing section 2. The Yperiphery of the plate 26 is circular, and closely fits a circular seat in the end of the casin 2, which insures perfect alinement of the L(bearing when the casing 2 and its plate 26 are in position in the machine. The periphery of the plate 26 also fits within tho casing section 1- of the controller, and insures the aiinement of the

sections

1 and 2. The shaft 25 is also supported at other points by suitable bearings in the

partition walls

27, 28 and 29 of the casin he winch drum 30 is splined to a hollow shaft or quill 31, which is concentric with the shaft l25, and the bearing for the quill 31 in the partition 28 is made in the form of a removable central plate or bushing 32.-

When thel

casing sections

2 and 3 are separated, the shaft 25 will be withdrawn with the section 2, as will hereinafter ap ear, but the quill 31 will remain in the section 3, being prevented from being withdrawn with the shaft 25 by the spline 33. The quill 31 may, however, be withdrawn through the partition 28 by first removing the bushing mesme 32. This allows of inserting and withdrawing the drum 30 through the opening 34 at the bottom of the drum casing 3, and allows the partitions 28 and 29 to be made integral with the other parts of the casing section 3.

The connection between the shaft 25A and the drum 30 comprises a gear train and the are Vhoused within the respective compartments mechanical brake mechanism which oil, the casing section 2 has an oil hole 35,y

F ig.-7, which is so located as to overflow after the oil has reached the desired level. This oil hole is closed by a cap 36; By preference, the gear train is made up of a series of alternate pinions 37 and gears 38, the inions being all of equal size, and the gears being also all equal in size.y The first of the pinions 37 is fixed on a quill 39, which is concentric with the shaft 25, and the last of the gears 38 is fixed on the quill 31. There are twoseparate trains of intermediate gears connecting said first pinion 37 and last gear 38, and as half of the load is thus taken by each gear train, the strain on each individual gear tooth is reduced to one-half of what it would bein the case of a single gear train, thus reducing'tlie liability of breakage of the gears and making it possible to reduce the size of the gears for any given load. f

The mechanical brake comprises a pair of

friction disks

40 and 41, concentrically mounted with respect to the shaft 25 but in axial alinement with each other. The disk 40 is keyed tothe quill 39, and the disk 41 is supported by, but loose, on the shaft 25. Relative rotation of the

disks

40 and 41 is prevented by means of the pins 42, which are rigidly secured in one of said disks and axially slidable in the other. The two disks are urged apart by means of helical springs 43 surrounding the pins 42. rThese disks together constitute an expansible clutch member, which, through its expansion and contraction, may be forced into or withdrawn from driving engagement with the clutch member 44, with which it cooperates. The clutch member 44 consists of two disks located for frictional engagement with the adjacent faces of the

disks

40 and 41 respectively, and rigidly connected together. The member 44 is journaled .to rotate concen-l trically `of the shaft 25, but is driven only through its frictional connection with the

disks

40 and 41. The member 44 has an air nul-ar fiange 45 located to co-act with friction ratchet pawls or toggles 46, which are mounted on the partition 27 of the casing section 2,and arranged toV automatically lock the member 44 against rotation in one direc tion, while permitting its free rotation in the other direction, as will be seen from Fig. 8. The pawls 46 carry at their outer ends riction shoes 47, which are faced with leather or other suitable material for frictional enagement with the inner peri hery of the ange 45. The pawls 46 are ield in posi# tion by pivot studs 48, but the boss 49 is provided with bearing surfaces 50 which fit the hubs of the pawls 46, and assist the studs 48 in withstanding the thrust of the pawls. The friction shoes 47 are normally urged into contact with the flange c45 by means of springs 5l.

From Fig. 8 it will be seen that the member 44 will be free to rotate in the direction of the arrow 52, as the frictional contact between the shoes 47 and the flange 45 swings the pawls 46 toward a position for reducing the pressure of the shoe against the flange. Rotation of the member 44 in the opposite direction causes the pawls 46, by virtue of said friction contact, to swingtoward a radial position, and thereby forces the shoes 47 outward and increases the frictional contact until the member '44 is eflectually locked.

A pair of diametrically opposite sets of toggle links 53 is interposed between the

disks

40 and 41, as may be best seen in Figs. 9, 11 and 12, for vthe purpose of drawing them out of engagement with the member 44. Each set comprises a pair of links pivotally connected to the

disks

40 and 41 respectively, and joined at their adjacent ends by means of arms or studs 54 carried by a hub 55, which is fast on the shaft 25. The studs 54 have ball shaped enlargements fitting the apertures in the adjacent ends of the .toggle links 53. This form of pivotal connection between the links is provided on account of the necessary angular movement of the studs 54 in the apertures. The toggle links are so placed that when the shaftf25 is rotated in the normal direction for winding the hoisting cable on to the drum 30 for lifting a load, the toggles will force the

disks

40 and 41 into driving engagement with the member 44. When, therefore, the shaft 25 is stationary, the pull of the load on the drum 30 will have the same effect of' expandin the toggles and forcing the disks 40 an 41 into gripping engagement with the surfaces of the member 44, but as the member 44 is locked by the pawls 46 against reverse rotation, it automatically locks-the load at any position through the mere. stopping of the motor. If, however, the moto-r is reversed, the pull of the shaft 25 on the toggles 53 pulls the

disks

40 and 41 toward each other against the action of the springs 43, thus releasing the

disks

40 and 41 from the brake member 44, and allowing the pull ofthe load on the 4drum 80 to unwind the cable from said drum. The unwinding of the cable is, however, controlled by thel speed of reverse rotation ofthe motor, since any tendency of theload to cause the disk. 40 to rotate at a speedl in excess of that of the shaft 25 will remove the pull on the tog gles and allow the springs 43 to force the

disks

40 and 41 into frictional engagement with the brake member 44. As the member 44 cannot rotate in such reverse direction, the unwinding of the hoisting cable 56 cannot take place except while the shaft 25 is turning so as to pull the

disks

40 and 41 awayfrom the member 44, as above described.

In the section 5 of the casing, there is i The brake shoes 58 are withdrawn from such frictional engagement by means of electro-` magnets 60, which are connected in the same circuit with the stator windings of the motor, so that whenever the motor windings are energized, the electric brake will be automatically released, but as soon'as the electric current is cut off from the motor, the magnets release their armatures and the springs 59 will force the shoes 58 into engagement with the wheel 57 and stop the shaft 24, and, through it, the shaft 25. The electric brake supplements the mechanical brake, and gives additional holding power at times when the current is cut of, since it locks the shaft 25, and thereby causes the pull of the load on the cable to expand the toggles 53, and increase the frictional grip between the

disks

40 and 41, and the member 44.

The operation of the device shown is as follows The controller is so arranged that when the operator pulls down on the cord 7, the windings of the motor will be energized, and the' electric brake will be automatically released. The motor, acting through the shaft 25, the member 55, and toggle links 53, drives the disk 40, and through the connected trains of gears, rotates the drum 30 so as to hoist the cable 56. During this-movement, the

disks

40 and 41 are forced into gripping engagement with the clutch member 44, but the direction of rotation is such that the ratchet brake shoes v47 allow the member 44 to rotate freely. In case the motor is no w stopped, the pull of the load on the hauling cable 56 would tend to drive the parts in the reverse direction, and this causes the ratchet brake shoes 47 to grip the member 44. As the

disks

40 and 41 are normally urged by the springs 43 into gripping engagement with the clutch member 44, the locking of said member 44 by the ratchet brake shoes there.- i'orc locks the druln. also secures the armature against rotation, any tendency of the disk 40 to slip relatively of the member 44, would-cause the toggle links 53 to be set up by the member 55, so

as to force the

disks

40 and 41 into still:

tighter engagement with themember 44. W hen the cord 7 is pulled down for starting the motor, the shoe 12 of the automatic cutout mechanism is lowered. If it should happen that the operator fails Lo stop the` motor before the hook 9 had reached the extreme u )ier limit of its 'movement the;

sheave 13 will engage the shoe 12, and cause the crank 10 to reset the controlling lever to its off position, and stop .the motor. In order to cause the load todescend, it is necessary to reverse the motor, but the brake` mechanism is so designed that the motor need exert merely enough power to release kthe brake, thus allowing the load to descend by its own gravity. The reverslng of the motor may be accomplished in any usualE such excess speed would set the mechanical brake and cause the load to .be locked to the frame until the rotation of the shaft 25 again releases it, as has been explained. The mechanical brake thus acts to automatically lock the load in any position, and permit it As the electric brake 'nal to said casing andvcomprising in to descend only at a speed corresponding to the speed of the shaft 25 when driven in a reverse direction. y

Although but one specific embodiment of this invention is herein shown and described, it will be understood that numerous details of the construction shown may be altered or,

omitted Without departing from the spirit of this invention, as defined by the following claim.

I claim:-

In a hoist, the combination of a casing, a winch drum journaled in said casing, a motor mounted in said casing at one side .of said drum, operating mechanism mechanically interposed between said motor and drum,l a controller mounted in said casing t at the side of said drum which is distant from the motor, said casing comprising a central section within which said drum is mounted, and individually removable sections respectively carrying said motor, operating mechanism and controller, means connected to ,the section of the casing containing the Winch drum for supporting the casing, wiring entering said casing at said suporting means and connecting an outside source of electricity with said controller and motor, and a housingfor said Wirin 'extervidual closed terminal boxes for said motor and controller, and a conduit coimccting said terminal boxes, said conduit and terminal boxes being adapted to permit ready access from the exterior to said Wiring. Signed at Chicago this 10th day of Nevember, 1910.

HARRY B. SHREVE.

Witnesses:

EUGENE A. RUMMLER, MARY M. DILLMAI.