US814828A - Safety lowering device. - Google Patents

Description

PATENTED MAR. 13, 1906.

MA WINVENTORS B) QJ/ ATTORNEY v. R. & E. H.. BROWNING. SAFETY LOWBRING DEVICE.

APPLICATION FILED MAYIIO, 1904.

WITNESSES: we www WW6);

UNITED STATES PATENT OFFICE.

VICTOR BROWNING AND EARL H. BROWNINQ-OF NOTTINGHAM,

-SAFETY LOWERING DEVICE.

Specification of Letters Patent.

Application filed May 10, 1904. Serial No. 207,343.

To all whom, it may concern: I

Be it known that we, Vrcron R. BROWN- ING and EARL H. BROWNING, citizens of the United States, residing at Nottingham, in the county of Cuyahoga and State Ohio, have invented a new and useful Improvement in Safety Lowering Devices, of which the following is ,a'specification.

This invention relates to hoisting machinery, andhas particular reference to. an automatically-controlled safety lowering device for the same, the object of the invention being the production of a device of this 'charac ter which will throw itself out of operation while hoisting a load, but which will upon the reversal ofthehoisting-motor automatically said view also showin control the descent of the load, and thus prevent any possibility of accident.

In the accompanying drawings, forming a part of this application, Figure 1 is a plan view of a trolley for use in hoisting machinery, diagrammatically electrical connections or controllin the same. Fig. 2 is a fra mentary sectiona view taken substantially t rough the center of the disks and ratchet-rings of the safety lowering device, and Fig. 3 is a view taken at right angles thereto on the line 3 3 of Fig. 1.

I In the raising and lowering of heavy loads there is always danger of some breakage in, the machinery or of too sudden descent of the load, either of which will result in a loss of control of the latter, which is liable to cause serious accident. It is therefore desirable to interpose in the train of the hoisting mechanism a safety device which is always ready to arrest the machinery in case either of the above contingencies arise. r

In the patent issued to E. H. Browning and Victor R. Browning January 27, 1903, No. 719,182, there is shown a hoisting mechanism similar to the one that is represented in Fig. 1 of this application, said patent also showing a conventional formof safety lowering device. Inasmuch as substantially the same mechanism for hoistin and the same electrical connections are shown in said'pa'tent, I will refer to the same for a'description of these parts and will make the resent description as brief as will suffice to disclose the subjectmatter of the present invention.

I Referring to the accompanying drawings, in which similar reference characters designate corresponding parts throughout the several views, 1 represents the hoisting-drum of the trolley, and 2 the motor for drivin the same, said motor being geared with the rum by suitable mechanism.

3 is the commutator of an electric generator which furnishes the current for driving the motor, and 4 is a controller by means of which the direction of the current .through the field-magnet coils may be reversed.

' The conductors leading to the field-magnet coils are connected with the motor at the points F F, and the conductors leadingto the armature are represented at A A. As is well known, the direction of rotation of the motor-armature can be reversed by simply reversing the direction of the current through the fields or-through the armature. The connections shown are intended to reverse the current through the fields. The disks and ratchets of the safety lowering device are shown in Fig. 1 as mounted upona shaft 5, said shaft also carrying gears 6, 7, and 8, through which power may be transmitted to the hoisting-drum. The gears. 6 and 7 are mounted upon a sleeve 9, which is loose upon the shaft 5, and the gear 8 is secured to the shaft. The end of the sleeve 9 next to the safety lowering device is provided with helical surfaces 1,0, which contact with corresponding surfaces on the adjacent disk of the lowering device, one of said latter surfaces being indicated at 11 in Fig. 2. The sleeve 9 and the various disks and ratchetrings ofthe safety lowering device are so proportioned that they almost cover the shaft 5 between its end bearings. I

By referring to Fig. 2 it will be seen that the safety lowering device has outer disks 12 and 13 and an inner disk 14, between which are mounted the ratchet-rings 15. The disks are so mounted on the shaft that there may be a slight lateral movement thereon; but thegare forced by the key 16 to turn therewit As will be understood, when the motor 2 is started the shaft 5 will be held from turning because of the resistance due to the gearing and to the load until the sleeve 9 camsthe disks 13 and 14 laterally into close frictional engagement with the ratchet-rings 15, after which the sleeve and the disks move together as one shaft. The pitch of the helical SUI". faces is so slight that when the current is thrown off of the motor the sleeve and disks will not move apart, but will remain in the position to which they were forced when the motor was turning. This being true, it will be obvious that if the disks are held from rotation the entire mechanism will be held less the rings slip between the disks, and the friction between these parts is so great that there can be no movement unless the motor is actually driven in a reverse direction.

It is desirable to have the pawl 17 entirely disconnected from the ratchet-rings while the load is being hoisted, and for this reason we provide electrical means for drawing the pawl backwardly out of engagement at this time, said means being shown most clearly in Figs. 1 and 3. I 18. represents an armature-plunger which is adapted to be acted upon by the coils of the two solenoids 19 and 20. One of these solenoids is connected, through the wires 21 and 22, with the field-magnet coils of the motor, and the other solenoid is connected, through the wires 23 and 24, with the armature-circuit. These two solenoids are arranged concentrically about the armatureplunger, and for the purpose of increasing their magnetic effect they are surrounded by an iron shell 25. Also-in order to prevent the entrance of dust within the shell the opening into the latter opposite the plunger is closed by a suitable plug 26. From this description it will be understood that when the armature-plunger is drawn into the solenoids the pawl 17 will be released from engagement with the ratchet-rings and the latter will be free to turn while the motor is hoisting the load. In order to attract the armature in this manner, however, it is necessary for the currents in the solenoids to flow in the same direction, so that they will add their strengths together. When, however, the current is reversed in the field-coils of the motor, it is also reversed in the solenoidthat is, in series therewithso that the current in one solenoid substantially neutralizes the magnetic effect of the current in the other solenoid,-with the result that there is not sufficient attraction of the armature-plunger to prevent the engagement of the pawl with the ratchet-rings, as the pawl is weighted at its lower end, as shown at 27, so that it is tipped forward into engagement with the rings.v This same action takes place when the current is cut oil' entirely, so that when the motor is stopped altogether or when it is driven backwardlv while the load is being lowered the pawl will be in engagement with the rings and will hold the load under complete control.

Having thus described our invention, what we claim as new, and desire to secure by Letters Patent of the United States, is

1. In hoisting apparatus, a driven member, a motor for turning said member, and gearing connecting said motor and member, a safety lowering device in said gearing, said device having a solenoid that is in series with the motor, and means for reversing the direction of current through said solenoid and motor.

2. In hoisting apparatus, a driven member, a motor for driving said member, and gearing connecting said motor and member, a safety lowering device in said gearing, said device having clamping-disks and ratchetwheels,

and a pawl adapted to engage said ratchet wheels, a solenoid adapted to control said pawl, connections placing said solenoid in series with the said motor, and means for reversing the current through the said solenoid and motor, for the purpose specified.

3. In hoisting apparatus, a motor, a driven member, and gearing connecting said motor and member, a safety lowering device interposed in said gearing, said device having clamping-disks and ratchet-rings, and a pawl for engaging said rings, a plunger connected with said pawl, and a pair of solenoids surrounding said plunger, one of said solenoids being in series with the motor-armature, and the other solenoid being in series with the motor-fields, and means for reversing the direction of the current through one of the solenoids.

4. In hoisting apparatus, a motor, a driven member, gearing connecting the motor and member, and a safety lowering device interposed in said gearing, said device havin clamping-disks and ratchet-rings and a paw for engaging with said rings, said pawl being adapted to normally engage the rings, a plunger connected with said pawl, and a pair of solenoids surrounding said plunger, one of said solenoids being in series with the motorarmature, and the other solenoid in series with the field-coils of the motor, and means for reversing the current through the fields, whereby when the motoris turned in a reverse direction, the currents in the solenoids will flow in opposite directions and will thus neutralize their effect upon the plun er so that the pawl can engage with the ratchet-rings.

5. In hoisting apparatus, a motor, a driven member, gearing connectin said motor and member, a safety lowering device interposed in said gearing, said device having clampingdisks and ratchet-rings and a pawl f or engaging said rings, a plunger connected with said pawl, and a pair of solenoids surrounding the plunger, one of said solenoids being in series with the motor-armatnre and the other solenoid in series with the motor-fields, a me tallic shell surrounding the said solenoids, and means for reversing the current throu h the armature-fields and one of the solenoids, for the purpose specified.

j .and for 6. In hoisting apparatus, a motor, a driven member, earing connecting said motor and said mem er, a safety lowerin device interposed in said gearing, said iievice havin clamping-disks and ratchet-rings and a aw engaging said rings, and means for ho ding said pawl out of engagement with said rings while the motor-is turned vermitting the pawl to engage the rings whi e the motor is turnedin the reverse direction. f

7. In hoisting apparatus, a motor, a driven member, earing connecting said motor and said mem er, a safety lowerin device interposed in said gearing, said' evice having in one direction,

. [ii/""8 clamping-disks and ratchet-rings and a (pawl for engaging said rings, said paw beinga apted to engage the rmgs when the motoris stoppedor is turning in one direction, and

means for holding said pawl out of engagementwhile the motor is turned in the opposite direction. In testimony whereof We aflix our signatures in the presence of two witnesses.

. VICTOR RVBAROWNING.

' EARL' H /BROWN IN G.

Witnesses: Y W. H. WHEEL R,

H. B. STRONG:

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