US1908370A

US1908370A - Gear motor

Info

Publication number: US1908370A
Application number: US506661A
Authority: US
Inventors: Earl B Lear
Original assignee: Ingersoll Rand Co
Current assignee: Ingersoll Rand Co
Priority date: 1931-01-05
Filing date: 1931-01-05
Publication date: 1933-05-09
Anticipated expiration: 1950-05-09

Description

E. B. LEA'R GEAR MOTOR -'ylay 9, 1933.

Filed Jan. 5, 1951 IN VEN TOR. ll., mir BY /r l Leal'. .fc

Patented May 9, 1933 EARL 1B. IEAIRJ, OF PHILLIPSBURG, N'EVVl JERSEY, AssIGNon 'ro Indumenti-RAND COMPANY, OF J'ER-SIEYv CITY,NEW JERSEY, A CORPORATION OF NE'WJERSE-Y I GEAR Moron Application med Janaary 5, 1931. seriai No. 506,661.,

This invention relates to gear motors, but more particularly to a gea-r motor that is automatically responsive to an increase in power requirements.

The object of the invention is to provide a gear ymotor which willy operate at a high degree of efficiency from a point of minimum power requirementto its maximum capacity.

@ther objects will bein partobvious and in part pointed out hereinafter. i p

The objects above referred to are accomplished by the mechanismshown inthe ac` companying drawing, in-which Figure 1 shows a front elevation of a hoist with the motor attached partly in section.`

Figure 2 is a sectional viewl of Figure 1 taken on the line 2`2 looking in the direction indicated by the arrows. Y

Referring more particularly tothe drawing a hoist 10, notshown in detail since it formsl no partV of .the invention, is-provided withy a drum 12 operatively -connected through reduction gearing (not shown) `in the'case 14 toashaft 16. v 1

A casing 18 secured to a frame member 2O of the-,hoist 10 is adapted `to

house gears

24, 26, 28 and 80 ofv a gear motor 82. AA cover plate 19 provides a closure for the 'end ofthe casing 18 and theA casing 18,'-plate 19 and member* 20' are held togetherv by bolts 22. Shafts 34, 36 and 38 are journaled in the frame 20 and

gears

24, 28 and 80 rotate on' the shafts 84 36 and 38, respectively, Gear 26 is keyed to sha-ft 16 by means of a key 40. An enlargement 42 on the 'casing 18 is adapted to house a valve 44. A valve chamber 46is formed in the enlargement42. The' valve 44 is of thediiferential type having heads`48 and 50 ofwhich thehead 50 is the head of larger diameter and its inner endsurface constitutes an "actuating surface 51 again st which pressure fluid from supply constantly acts. The head 50 tits slidably in the valve chamber 46 and the head 48 vis adapted to slide in a reduced portion 52 of the valve chamber. A vent 54 leads from the atmosphere to the reduced bore-52.' In the head 50 a cup-shaped depression 5,6 isformed. A threadedplug 58 forms a closure for the valve chamber 46. The plug 58 is provided with a cup-shaped opening 60 and a set screw 62 'passes through the head of the plug 58 into the cup 60. A spring 64 iitted in the depres sion 56 and'acting against the head 66 of the set screw62 opposes movement of the valve 44 in the direction of the plug 58. A pipe 68V conducts pressure fluid "to a passage 7 0 and to the actuating surface 51 froma source of supply (not shown) .l An annular groove172 formed inthe inner surface o f the valve chamber 46 connects with aV passage 74'lead'- ing to an inlet port V76 between the

gears

28 and 30. y 1 Y A i vA valve assembly similar to that described f above is found on the opposite side of the casing 18.'A This valveassembly comprises a valve 78 having heads 80" and 82, a'valve chamber 84, a reduced extension 86 of the valve'cha-mber, a set screw 90 having a head` 92, a spring 94 and an annular passage 96.',

A passage 98 leading from the annular passage 96 connects with appipe 100 which leads on the gear teeth by the pressure fluid.` Por" tions of the motive Huid will'of course "be entrapped between the wall of the casing and each pair 'of gear teeth. This motive fluid to an inlet port 102 between the gears 24 and `The operation of the motor is as follows:

will be dischargedto the atmosphere throughV Y ports 104and 106.l It will bevobvious that the shaft 16 will be caused to rotate by rotaltionof the

gears

26 and 28. Rotation of the shaftwill be carried'to the drum of the hoist 12 through the reductiongears which are not shown, thereby causing the drum 12 to rotate and the cable 108 to be wound about the drum 12. Assuming that too great a load is placed on the cable 108 the

gears

26 and 28` will fail to rotate fast enough and'fluid pressure will build up in the passage andact upon the valve 44 forcing it 'downward against the resistance of the spring 64there-z by opening passage 7 4 to the source of pressure fluid'. Pressurel fluid will flow through the passage 74 and from the port 76 between the

gears

28 and 30. The pressure fluid entering the port 76 will act upon the

gears

28 and 30 causing them to rotate in a counter clock-wise and a clock-wise direction, respec-V tively.

If the

gears

28 and 30 are able to rotate with sufficient rapidity to prevent a building up of pressure in the passage 7 4, the valve 78 will remain in the closed position, as shown in the drawing and conditions of load on the hoist and pressure fluid supply to the motor will be such that the'load is handled efficiently by the motor. If, however, the

gears

28 and 30 rotate so slowly that pressure builds up in the passage 74 the valve 7 8 will be opened by pressure acting on the head 82 and pressure fluid will enter the annularpassage 96 and be conducted by the pipe 100 to the port 102. Pressure fluid will then act upon gears 24 and 26 tending to cause them to rotate in a counter clock-wise and a clock-wise direction, respectively, thus increasing the power ofthe gea-r motor by substantially three-fold.

Ports 54 and 55 leading to the bores 52 and 86, respectively, prevent the formation of a vacuum behind the

heads

48 and 80 of the valves 44 and 78, respectively. Ports and 112 permit the exhaust of pressure fluid'from the valve chambers 46 and 84, respectively, and rthus prevent back pressure fromacting on the valves 44 and 78 when anincrease in fluid pressure tends to open them. The tension on the springs 64 and 94 is adjusted by the set screws 62 and, 90, respectively. A

When the gears 24 and 30 are not in use as auxiliary motors they are necessarily turning with the motor. Unless the inlet side of these gears is vented, they will act as vacuum'pumps, load the motor, and waste power either through the increased load or through opening the valve heads which admit pressure fluid to their inlets and cause them to act as auxiliaries.

In order to permit these gears to idle, ports 109 and 111 are provided in the valves 50 and 82 so that when the valves are in closed position with respect to their function as fluid supply valves they are in position to act as vents by connectingthe liuid supply passages to atmosphere. the

motor comprising ygears

28 and 30 is vented through'passages 74, 7 6 and 106, valve chamber 46 and vent 110; The inlet side of the motor, comprised of gears 24 and 26, is vented through its corresponding passages.

Assuming that the motor must overcome static friction in the bearings of the hoist, as in starting, it will be noted that if the load is too great for

gears

26 and 28, the valve 44 will be opened and pressure fluid delivered to gears The inletv side of

Y

28 and 30, thereby doubling the force exerted onthehoist. Should that force be insufficient another pair of gears will'be automatically supplied with pressure fluid, and so on until the hoist is started. However, once the static friction is overcome, the consumption of pressure fluid will be automatically reduced in accordance with the power required to run the hoist. And thus the objects hereinbefore re ferred to are accomplished. I claim: f

1. A gear motor comprising a casing, a pair of motor gears rotatably mounted therein, a

fluid supply passage thereto and fluid outlet passages therefrom to admit and discharge pressure fluid for actuating the motor, an additional gear in the casing entrained with one of said gears and rotatable therewith, and means in the casing to automatically admit pressure fluid to the additional gear and thus cause it to coact with said motor gears as an auXiliary thereto. s l v 1 2. A gear motor comprising a casing, a pair of motor gears rotatablymounted therein, a fluid supply passage thereto and fluid outlet passages therefromto admit and discharge pressure fluid for actuating the motor,

an additional gear in the casing entrainedA with one of said gears and rotatable therewith, a connecting passage from the inlet side of the motor to an opposite' side thereof between one of the firstmentioned gears of said motor and said additional gear,vand means in said passage to automatically admit pressure fluid to the additional gear and thus cause it to coactwith said motor as an auxiliary thereto.

3. A gear motor comprising acasing, a pair of motor gears rotatably mounted therein, a fluid supply passage thereto and fluid'outlet passages therefrom to admit and discharge pressure fluid for actuating the motor, anadditional gear in the casing entrained with one of'said gears and rotatable therewith, a connecting passage vfrom the inlet side of VVthe motor to an opposite side thereof between one gear of said motor and said additional gear, and means including a valve chest and a valve therein to admit pressure fluid through the connecting passage to the additional gear in one Vposition of the valve, and passages in the valve chest and valve to communicate the connecting passage with the atmosphere in another position ofthe valve.

4. A gear motor comprising a casing, a pair of motor gears rotatably mounted therein, a fluid supply passage thereto andfluid outlet passages therefrom to admit and discharge pressure fluid for actuating the motor, an additional gear in the casing entrained with one of said gears and rotatable therewith, a connecting passage from the inlet side of the motor to an opposite side thereof between one gear of said motor and said additional gear, and a valve in the casing having an actuating Surface exposed to pressure fluid in the supply passage whereby, upon an increaseinthevalue of the pressure fluid in the supply passage, the valve is actuated to admit pressure fluid into the connecting passage and thus cause the additional gear to coact with said motor as an auxiliary thereto.

5. In a gear motor, a casing, a pair of motor gears mounted therein, a pressure Huid supply inlet between said gears to deliver actuating fluid thereto, separate exhaust outlets for each gear, an additional gear in the casing entrained with one of said gears, a connecting passage fromthe inlet side of the motor to an opposite side thereof between one gear of said motor and said additional gear, and a pressure fluid actuated valve subjected to fluid supply and being responsive to fluctuations in the value of the fluid supply to establish and cut-off communication between the source of supply and the connecti ing passage.

' 6. In a gear motor of the relay type, a casing containing a primary gear motor having a plurality of gears, and an auxiliary gear entrained with one of the gears, a fiuid inlet between the gears of the primary motor, a second fluid inlet to deliver pressure fluid to the auxiliary gear, a valve chest having a valve chamber and a port and connecting said iiuid inlets, avvalve in said valve chest to control communication between the iluid inlets and being responsive to variations of pressure in the fluid supply, a spring to hold the valve in position to block communication between said iiuid inlets when the motor is 0perating under light load conditions, said valve having a port to register with the first mentioned port for opening said second fluid inlet to atmosphere, and an actuating surface on the valve against which pressure fluid acts to open communication between said fluid inlets and to close said second fluid inlet to atmosphere when the motor is under increased load.

In testimony whereof I have signed this specification.

EARL B. LEAR.