US2541283A - Gear lapping - Google Patents

Description

W. S. PRAEG GEAR LAPPING Feb. 13, 1951 2,541,283

Filed July 6, 1948 3 Sheets-Sheet 1 INVENTOR.

WALTER S. PRAEG yjimw,w y/g/w ATTORNEYS Feb. 13, 1951 W. S. PRAEG GEAR LAPPING Filed July 6, 1948 3 Sheets-Sheet 3 WvA M WALTER S. PRA EG ATTOR N EYS Patented Feb. 13, 1951 2,541,283 GEAR LAPPING Walter S. Pracg, Detroit, Mich., assignor to National Broach & Machine Company, Detroit, Mich., a corporation of Michigan Application July s, 1948, Serial No. 31,132

7 Claims.

The present invention relates to apparatus for lapping gears and more particularly to a machine including mechanism for feeding lapping compound into the meshing zone.

It is an object of the present invention to provide in a gear lapping machine mechanism for feeding lapping compound into the zone of mesh between a gear-like lap and a gear in predetermined amounts and at predetermined intervals.

More specifically, it is an object of the present invention to provide means for feeding a semisolid lapping compound between a gear and gearlike lap, including a flattened nozzle to supply the semifiuid lapping compound in ribbon form.

It is a further object of the present invention to provide a gear lapping machine comprising means for rolling a gear and gear-like lap in mesh, means for relatively reciprocating a gear and gear-like lap in a direction which occupies a plane parallel to the axes of both the gear and lap, means for reversing the rotation of the gear and lap at the end of a stroke. of reciprocation, and automatic means for feeding a predetermined amount of semisolid lapping compound into the zone of mesh between the gear and lap at the approach side of the teeth thereof.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a front elevation of a gear lapping machine embodying the present invention;

Figure 2 is a top plan view of a portion of the means for feeding lapping compound;

Figure 3 is a section taken on the line 3-3 of Figure 2; and

Figure 4 is a partly schematic wiring diagram of the gear lapping machine.

Referring now to Figure 1 the gear lapping machine comprises a base l having an upwardly extending pedestal l l terminating in a forwardly projecting overhanging portion 12. Angularly adjustable about a vertical axis beneath the overhanging portion I2 is a rotary support l3 including means for mounting a gear-like member ll thereon. Drive means including the motor (not shown) are mounted in the portion l2 and are connected to the gear-like member I4 through suitable driving mechanism.

On the forward portion of the column II is a vertically adjustable knee l5 upon which is mounted a carriage l6. Intermediate the carriage l6 and the knee l5 are horizontally extending ways by virtue of which the table It may be reciprocated back and forth, that is from disclosed in Drummond Patent 2,157,981.

right to left as seen in Figure 1. Details of this mechanism form no part of the present invention and are fully disclosed in Drummond Patent 2,270,421.

Located on the carriage i6 is a rocking table 20 which is pivoted to the table for rocking motion about a horizontal axis as by a trunnion indicated at 2 i. Suitable cam means indicated genorally at 22 are provided and are rigidly mounted on the column l5. The cam follower carried by the rocking table 20 engages the cam and may be employed to effect a predetermined rocking movement of the table 20 in timed relation and in response to back and forth reciprocation of the carriage l6. Details of this construction form no part of the present invention and are fully The rocking table 20 carries at its top a support member 25 which is mounted for angular adjustment with respect to the table 20 about a vertical axis and which is adapted to be clamped in adjusted position by suitable means (not shown). Adjustable stocks 28, 29 are provided on the support member 25 for supporting therebetween a second gear-like member 30.

The gear-like members It and 30 may be brought into engagement by vertical adjustment of the knee IS on the column III. In this type of gear finishing it is desired to have the axes of the gear-like parts crossed at an angle between 3 and 30 degreesand this condition may be brought about by angular adjustment of the adjustable support l3 or the supporting member 25 or both. As previously stated, means are provided for efiecting back and forth reciprocation of the carriage I6. It will be readily apparent that by appropriate adjustment of the angular adjustment of the support 13 and the supporting member 25, the desired angularity between the direction of reciprocation and the axes of the gear-like parts may be achieved.

Suitable driving means are provided for effecting back and forth reciprocation of the carriage l6 and for effecting rotation of the positively driven gear-like member l4. Suitable controls are also provided and these may take the form of switch actuating dogs 35 and 36 adapted to be engaged upon reciprocation of the carriage l8- by adjustable bolts 31 and 38. By this means reciprocation of the carriage I6 is limited by engagement between a bolt 31 and a dog 35 on the one hand and bolt 38 and dog 36 on the other hand. Furthermore, the direction of rotation of the members [4 and 30 is preferably reversed at the end of each stroke of reciprocation and the switches controlled by the dogs 35 and 38 may effect this reversal of rotation.

The lapping operation is normally carried out with a cast iron lap and in order to remove metal from the part being lapped, a suitable abrasive lapping compougi is introduced onto the teeth of the lap. In the past this has been accomplished in a crude manner by dipping a brush in lapping compound and brushing the teeth of the lap. This results in very poor control of the amount of lapping compound applied and further a good part of the lapping compound may bethrown off by centrifugal action and waste.

In accordance with the present invention a relatively viscous or semisolid lapping compound is employed and it is applied in predetermined equal amounts at definite intervals during the lapping operation. Furthermore, it is applied in the form of a thin ribbon so that it will appear uniformly from end to end of the teeth of the lap.

The means for feeding lapping compound includes a reservoir 39, and a flexible conduit 40 terminating in a flattened nozzle 4| which is.

located adjacent the zone of mesh between the gear-like members l4 and- 30. It may be mentioned at this time that either the member l4 or the member 30 may be the lap, the other of these two members of course being the gear to be lapped.

In order to apply the lapping compound for maximum emciency and with a ,minimum of waste it isdesirable to apply the lapping compound in the form of a thin ribbon directly into the bight at the zone of mesh between the gear and the lap, and furthermore, to so time the compound feeding operation that the lapping compound is introduced onto the teeth of the gear and lap at the approach side of mesh. It is further desirable for the feeding operation to take place in such a. manner that lapping compound is spread more or less uniformly around the periphery of the lap and/or gear. However, since the teeth of the lap and gear will in all cases be of different number, and since the rate of rotation of these parts is relatively high, lapping compound will be spread more or less uniformly due to the meshing engagement of the teeth of the gear and lap.

Referring now specifically to Figures 2 and- 3 the compound feeding structure comprises the reservoir or container 39 which as best seen in Figure 2 is of generally U-shaped cross section having a recess 42 provided therein for the reception of the feeding mechanism indicated generally at 43. The reservoir 39 has a hinged cover 44 which may be raised to supply the semisolid or viscous lapping compound to the reservoir. At the bottom of the recess 42 is a ledge 45 having an opening therein in which is provided a flexible diaphragm 46 which may be formed of neoprene or other suitable material. Connected centrally to the diaphragm 46 is a plunger 41, the lower end of which extends into a short tubular bushing. or sleeve 48 provided in the bottom wall 49 of the reservoir 39. Secured to theupper end of the plunger 41 is a rod 50 which is connected at its upper end as indicated at to the core 52 of a solenoid 53 having windings indicated at 54. A compression spring 55 is provided between a disc 56 connected to the upper end of the plunger 41 and a head 51 formed on a tubular guide 58 in which the rod 56 reciprocates.

At the lower end of the sleeve 48 is the flexible tube 43 terminating in the flattened nozzle 41 previously referred to. The conduit 46 may be in fact particular means have been designed to permit pressure feeding of this fiuid by a mechanism which will not be subjected to excessive wear by the abrasive. For this purpose the sleeve 48 has an internal diameter sufliciently larger prevent wear taking place between these surfaces.

l On the other hand the amount of clearance is sufliciently small so that these two elements operate efliciently as a force feeding device for a semisolid material.

It is. desirable in feeding this abrasive compound to provide a relatively slow feed and accordingly, the plunger 41 is connected to the solenoid 53 in such a manner that upon energization of the solenoid the plunger 41 is withdrawn from the sleeve 48 by an amount sufficient to permit now of compound into the sleeve. The operation of the solenoid is of course extremely rapid but the withdrawing stroke of the plunger 41 is not a pumping stroke. When the solenoid 53 is de-energized the plunger 41 is urged toward and into the sleeve 48 by the compression spring 55. The strength of the compression spring 55 is selected such that a relatively slow control movement of the plunger 41 results. Accordingly, lapping compound is expelled from the flattened nozzle 42 at a controlled rate. Due to the flattened shape of the nozzle 41 the abrasive compound is formed into aribbon which is thus spread upon the teeth of the gear or lap.

The'circuit in which the windings 54 of the solenoid are included is connected to the switches actuated by the dogs 35 and/or 36 so that the feeding of the lapping compound takes place at the end of a stroke and further at a time when the rotation of the parts [4 and 34 is away from the nozzle 4|. Accordingly, lapping compound is immediately rolled between the teeth of the parts before any of the material can be thrown off by centrifugal action.

Referring now to Figure 4 the control mechanism is illustrated. The reciprocable carriage I6 is designated to be reciprocated back and forth by a conventional feed screw mechanism comprising a feed nut 60 and feed screw 62, the latter being driven'through a gear box 63 from a motor 64. The switch actuating dogs 35 and 38 previously referred to are connected to normally open switches 65 and 66 respectively, which are adapted to be closed by engagement with the adjustable bolts 31 and 38 respectively as the table reaches either limit of its stroke. The motor 64 is connected to a three phase circuit 68 through a reversing contactor 69.

Reversing the motor 64 by switches 65 or 66 is accomplished by completing a circuit from line 10, line 12, switch 66, line 13, to the reversing contactor, the circuit being completed through operate a solenoid therein to eil'ect reversing of the lines 18 and 11 to the motor. At the same time as a circuit is completed through the switch 08, a circuit is completed through the solenoid winding 54 through a line 18, switch 19, line 80, td'the solenoid windings and thence through the line 8! to the power supply. The switch ll is a double-throw switch which may cause the solenoid winding 54 to beenergized when either the switch 88 or'the switch 65 is closed, but not both.

Reversal of the reversing contactors by closing the circuit through the lines 13 and I4 reverses the motor 6.4 and causes initiation of reverse traverse of the table I 8. Eventually the dog 65 engages the bolt 31 and closes switch 65. At this time a circuit is completed through line 82, switch 65, and line 83 to the reversing contactor from whence the circuit is completed by a line 84 to the power supply. Completion of this circuit energizes an additional solenoid in the reversing contactor in the usual way and reverses the connections to the motor 64. At the same time, a circuit is set up through line 8!, switch 19, line 80, to the solenoid winding 54, and thence through the line 8| to the power supply.

Thus, by a proper selection of the switch 19 the solenoid 54 may be energized upon completion of a stroke oftraverse in either directiomand as previously indicated, this direction of traverse is selected such that as the abrasive compound is fed into the gear and lap, it is fed at a time when the adjacent portions of the gear teeth and lap teeth are moving away from the nozzle 4| so that the compound is introduced immediately into the point of meshing engagement between the teeth.

The drawings and the foregoing specification constitute a description of the improved gear lapping in such full, clear, concise and exact terms as tov enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is: I

1. In a gear lapping machine, pressure feeding means for lapping compound comprising a container having a recessed side wall spaced above the bottom wall of said container, a sleeve in the bottom wall of said container, the said recessed side wall providing a ledge spaced above I said sleeve, said ledge having an opening therein, 7

a flexible diaphragm closing said opening, a plunger connected to said diaphragm having a portion movable into and out of the upper end of said sleeve to expel lapping compound from said container, a solenoid for raising said plunger, and spring means for moving said plunger downwardly into said sleeve.

2. In a gear lapping machine, pressurefeeding means for lapping compound comprising a con tainer having a recessed side wall spaced above the bottom wall of said container, a sleeve in the bottom wall of said container, the said recessed side wall providing a ledge spaced above said of said reservoir beneath the level of lapping compound therein, a plunger in said reservoir having a loose lit in said sleeve and movable between a charging position in which the end of said plunger is withdrawn from an end of said sleeve and a feeding position in which said plunger enters said sleeve to expel compound from the other end thereof and means for actuating said plunger.

4. In a gear lapping machine, pressure feeding means for lapping compound comprising a reservoir, a tubular sleeve extending through a wall of said reservoir beneath the level of lapping compound therein, a plunger in said reservoir having a loose fit in said sleeve and movable between a charging position in which the end of said plunger is withdrawn from an end of said sleeve and a feeding position in which said plunger enters said sleeve to expel compound from the other end thereof, a solenoid connected to said plunger for efiecting withdrawal of said plunger from said sleeve, and resilient means for advancing said plunger on its feeding stroke.

5. In a gear lapping machine, pressure feeding means for lapping compound comprising a reservoir, a tubular sleeve extending through a wall of said reservoir beneath the level of lapping compound therein, a plunger in said reservoir having a loose fit in said sleeve and movable between a charging position in which the end of said plunger is withdrawn from an end of said sleeve and a feeding position in which said plunger enters said sleeve to expel compound from the other end thereof, a solenoid connected to said plunger for effecting withdrawal of said plunger from said sleeve, resilient means for advancing said plunger on its feeding stroke, and a flexible diaphragm secured to said plunger and sealing the solenoid mechanism from said sleeve.

6. In a gear lapping machine, a reservoir for semi-solid abrasive lapping compound, a tubular sleeve adjacent the bottom of the reservoir adapted to receive compound by gravity flow and the pressure head of the compound in the reservoir, a plunger located in alignment with said sleeve and movable between a position in which the end of said plunger enters said sleeve and a position in which said plunger is withdrawn entirely from said sleeve, said plunger having lateral clearance with respect to said sleeve to prevent wear by the abrasive compound, a spring urging said plunger toward and into said sleeve, and power means efiective to withdraw said plunger entirely from said sleeve to permit charging of said sleeve with compound.

'7. In a gear lapping machine, pressure feeding means for lapping compound comprising a container having a recessed wall providing a ledge spaced from an adjacent wall, said ledge having an opening therethrough, a sleeve in said adjacent wall aligned with the opening in said ledge and below the level of lapping compound in said container, plunger means having a plunger portion movable into and out of said sleeve to expel lapping compound from said container and a portion extending through the opening in said ledge into the recess, a flexible diaphragm closing the opening in said ledge and secured to said plunger means, and power actu-' ating means in the recess connected to said plunger means.

WALTER s. PRAEG.

(References on following P le) REFERENCES CITED Number I The following references are of record in the file 0! P t nt: I I v UNITED STATES PATENTS 5 2:851:842

Number Name Date 1,562,138, Copeland Nov. 24, 1925 N be 1,682,420 Rolf 1928 :39 J59 1,807,421 Mahoney May 26, 1981 Name Date Drummond Jan. 29, 1936 Kampmeier JuLv 8, 1941 Davis Oct. 26, 1943 Belhold June 20, 1944 FOREIGN PATENTS- Country Date Germany .4. Sept. 29, 1920

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