US1610232A - Lapping machine - Google Patents

Description

Dec. 14,1926. v J. N. BETHEL LAPPING MACHINE File d Feb. 2. 292: v

2 Sheets-Sheet fiderzf @cpfa Patented Dec. 14, 182$.

JOSEPH 1v. IBE'IHEL, or wono'nsrna, MASSACHUSETTS, ASSIGNOR 'ro BETHEL-PLAYER co, or WESTBORO, MASSACHUSETTS, A. COPARTNERSHIP consrs'rnxre or JOSEPH 1v.

BETHEL AND SIDNEY K11 521113.

nar rrivs MACHINE" Application filed February 2. 1 923. ,.Seria1 No. 616,474.

1 This invention relates to a machine for lapping steel bushings, studs or rolls or other articles'whi'ch are'to be brought quickly to accurate and uniform size.

Itis the object of my invention to improve the construction of such'lappin'g machines so that more accurate work canbe obtained andthat the cost of producing such accurate ture relates to the provision of means forvarying the eccentricity of the bearing member.

My invention further includes means for vertically adjusting the upper or fixed lap in the machine, said means permitting removal of the fixed lap from operative position in a horizontal direction while maintaining thevertical position thereof. I also disclose herein various arrangements and combinations of parts which will be herein after described and more specifically pointed out in the appended claims.

A preferred form of my invention is shown in the drawings in which Fig. 1 is a front elevation of my improved machine, with-certain parts shown in section;

Fig. 2 is an enlarged sectional elevation of the driving mechanism for the lower lap and eccentric work holder bearing member;

Fig.8 is a partial plan view of a work holder;

Fig. 4 is a plan view of the upper end of the eccentric bearing support and its driving shaft; I

Fig. 5 is a plan view of the adjustable eccentric bearing member and plate; I

Figs. 6 and 7 are a plan and side elevation respectively of a portion of one of the work holding arms; 7

Fig. 8 is a Side elevation of one of the work retaining collars; and

Fig. 9 is a detail sectional view showing the lost motion connection of the fixed lap. Referring to Fig. 1, I have shown alapping machine comprising a base 10 on which is mounted a post or standard 11 having a collar 12 which may be clamped, thereto in any desired vertical position. "Aridarm 13 has 'a' split hub or bearing portion 14v also mounted on the;post 11 and held in adjusted vertical position by the collar 12. The arm 13 may be swung in a horizontal plane about the axis of the post 11 and may be clamped in any desired position by upper and lower clamping devices 15 and 16.

At itsouter end, the arm 13 supports a sleeve 17 within which a rack bar 18 is slidably mounted. The rackpbar 18' is engaged by a pinion (not shown) ona cross shaft 19v mounted in hearings on the arm 13 and having a hand wheel 20 for rotation thereof.

A locking pawl 21 is pivoted on the arm 13 and engages a ratchet wheel 22 fixed to the shaft 19; by which action the rack bar 18 may be held in any desired vertical position.

A spider or head 23 on the lower end-of the rack bar 18 supports the non-rotatable lap. 24. The head 23 is preferably loosely fitted on the bar 18 (see' Fig. 9) to permit slight rocking movement relative to the bar 18 so that the lap 24 may angularly adjust itself to the surface of the work rotating beneatlr the lap. The head 23 and lap 24 are held from rotation by a suitable connection to the rack bar 18 which is of such form that the free rocking movement of the head is not interfered with.

The lower or rotatable lap 25 is mountedon a hub or flange 26 which is keyed to a hollow shaft or sleeve '27 rotatable in up per and lower fixed bearings 28 and 29 in the frame 10. A worm wheel 30'is fixed tothe sleeve 27'and is engaged by-a worm 31 on a drive shaft 32 The shaft .32 rotates in bearings fixed inthe frame 10 and is provided with tight and loose pulleys '33 and 34 for the usual belt drive (not shown).

An eccentric pin or hearing member 40 (Fig. 2) .is fixed on a slotted plate 41 (Fig. 5) which is transversely adjustable in guide ways 42 (Fig. 4) in a plate or disc'43 selcured' to the upper end of a shaft 44 freely rotatable in bearings'within the lap-driving sleeve 27. The plate 41 is secured in adjusted position in the guide ways 42 by a binding screw 45 at the upper end of the shaft 44.

A differential gear drive i provided he tween the sleeve 27 and the shaft 44. For this purpose a gear 46 on the lower end of the sleeve 27 engages a pinion 48 rotatable on a fixed stud 49 and having a slightly smaller pinion 50 mounted to rotate therewith. gear 51 on the lower end of the shaft 44. By these connections the shaft 44 is driven at a differential speed from the sleeve 27 which rotates the lap 2:3. The combination of gearing shown in the drawings provides a speed for the shaft 44 slightly slower than that of the lap 25. Under certain conditions it might be desirable to reverse the gearing shown in Fig. 1, thus driving the shaft 44 at a sligl'itly increased speed.

A work holder is mounted for free rotation on the eccentric pin or bearing mem her 40 (Fig. This work holder may he of any form adapted-to the work to be lapped and as shown herein comprises a disc or plate 53 having a plurality of arms 54 extending outward therefrom and preferably at an acute angle to the adjacent radii. This form of holder is adapted for supporting the cylimlrical sleeves or bushings S which are shown in Figs. 2 and 3. The arms are preferably provided with ]on gitudinal grooves 55 and transverse notches 56 and are adapted to receive locking collars 57 each having a stud 58 extending within the collar. These collars may be quickly placed in position by sliding the studs 58 along the grooves 55 to the desired position and thereafter turning the collars so that the studs will enter selected notches The work holder 52 is thus readily adapted to bushings of different lengths. This form of holder is illustrative only and in itself forms no part of my invention, which merely requires that the work holder be freely rotatable upon the pin or bearing Having described the construction of my improved lapping machine, the method of operation will be easily apparent. The work S is placed upon the arms 54 of the work holder 52 which is then mounted on the occentric bearing member 40, with the work resting freely upon the upper surface of the rotatable lap The upper lap 24 is then lowered until it engages the upper surface of the work, after which the machine is started and the lap 25 is positively rotated.

The eccentric pin or bearing 40 will also 'be positively rotated but at a slightly different speed and will give an eccentric motion to the center of the work holder 52 without imparting any positive rotation thereto.

The pinion 50 engages a release construction the Work is caused to engage every portion of the surface of both the fixed and movable la 5 and the differential eccentric motion has een found to possess very important advantages, particularly in respect to eliminating flat spots on cylindrical work. The work produced by this machine has been found greatly superior in this respeetto work produced by a similar machine in which the eccentric pin was driven at the same speed as the 'rotatalj le lap.

Having thus described my invention ,and the advantages thereof. I do not wish to be limited to the details herein disclosed oth-' erwise than as set forth in the claims, but what I claim is? 1. A lapping machine having, in combination, a fixed lap, a positively rotated lap, means including an outer driving sleeve for rotating said lap, an eccentric bearing member mounted'to rotate about the axis of said rotatedv lap, an inner driving shaft for'said eccentric bearing member rotatably supported in bearings within said outer driving sleeve, and positive driving-eonnections"be tween said outer driving sleeve and said inner drivin shaft effective to rotate said shaft simultaneously therewith but at a different speed.

2. A; lapping machine having, in combination, a fixed lap, a positively rotated lap, means incluing an outer driving sleeve for rotating said lap, an eccentric bearing member mounted to rotate about the axis of said rotated lap, aninner driving shaft for said eccentric bearing member rotatably supported in bearings within said outer driving sleeve, and positive driving connections between said outer driving sleeve and said inner driving shaft effective to rotate said shaft simultaneously therewithin the same direction but at a different speed.

3. A lapping machine having, in combina tion, a fixed lap, a positively rotated lap, means including an outer driving sleeve for rotating said lap, an eccentric bearing member mounted to rotate about the axis of said rotated lap, an inner-driving shaft for said eccentric bearing member rotatably supportecLin bearings within said outer driving sleeve, gears on .the lower ends of said driving sleeve and said inner shaft, and a pair oftransmitting gears secured together and rotatable about an axis parallel to the axis of said sleeve and meshing with said firstmentioned gears to cause rotation of said shaft at a speed different from the speed of said sleeve but in fixed relation thereto.

4. A lapping machine having, in combination, a fixed lap, a positively rotated lap, an eccentric bearing member mounted on a support to rotate about the axis of said rotated lap, positive differential gearing between said rotated lap and said eccentric bearing support, and a work holder freev member.

ly rotatable about said eccentric bearing I 5. A lapping machine having, in combination, a fixed lap, a positively rotated lap, an eccentric bearing member mounted to rotate about the axis of said rotated lap, a positive differential gear drive between said eccentric bearing support and said rotated lap. a work holder freely rotatable about said eccentric hearing member, and means to vary and adjust the eccentricity of said eecentric bearing member,

6. A lapping machine comprising a rotatable lower lap, 21 non-rotatable upper lap, means to raise and lower said upper lap, means to move said upper lap horizontally to and from operative position, means to hold said upper lap in horizontally adjusted position, and means to maintainsaid upper lap at a fixed elevation during such horizontal movement.

7. A lapping machine having a rotatable lower lap; at non-rotatable upper lap, means to rotate said lower lap, an a' rack bar supporting said upper lap, said bar and lap being loosely connected to permit limited equalizing movement of said upper lap while preventing rotation thereof. W

.In testimony whereof I have hereunto at fixed my signature.

[JOSEPH N. BETHEL.

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