US3668813A

US3668813A - Lapping machine

Info

Publication number: US3668813A
Application number: US127397A
Authority: US
Inventors: Jacques Barragan
Original assignee: R A STOKVIS AND FILS
Current assignee: R A STOKVIS AND FILS
Priority date: 1971-03-23
Filing date: 1971-03-23
Publication date: 1972-06-13
Anticipated expiration: 1989-06-13

Abstract

In a surface lapping machine in which workpieces to be lapped are confined in rings placed on the rotatable bed of the machine, the workpiece or workpieces in each ring being loaded by a cover and the rings being retained on the bed by arms provided with rollers, the arms being disposed in star formation and forming a rotary assembly which is movable stepwise around a vertical or substantially vertical shaft disposed coaxially or substantially coaxially with the bed, while at the periphery of the bed adjacent to the stopping positions of the rings there is disposed a plane, smooth table permitting the feeding of the rings to, and the withdrawal of rings from, the bed by sliding, there is provided an articulated arm with vertical pivoting axes which is pivotally mounted on said shaft, this articulated arm carrying a vertically guided raising means engageable with said cover.

Description

O United States Patent [151 3,668,813 Barragan [451 June 13, 1972 LAPPING MACHINE 3,505,766 4/1970 Boettcher ..5l/l29 3,521,409 7/1970 Day [72] Invent Jacques sceaux' France 3,570,188 3/1971 Ebner ..51/129 [73] Assignee: R. A. Stol-tvis & Fils, Paris, France Primary Examiner-Wayne A. Morse, Jr. [22] Filed March 1971 Attorney-Stevens, Davis, Miller& Mosher [21] Appl.No.: 127,397

Related US. Application Data ABSTRACT In a surface lapping machine in which workpieces to be lapped are confined in rings placed on the rotatable bed of the machine, the workpiece or workpieces in each ring being loaded by a cover and the rings being retained on the bed by arms provided with rollers, the arms being disposed in star formation and forming a rotary assembly which is movable stepwise around a vertical or substantially vertical shaft disposed coaxially or substantially coaxially with the bed, while at the periphery of the bed adjacent to the stopping positions of the rings there is disposed a plane, smooth table permitting the feeding of the rings to, and the withdrawal of rings from, the bed by sliding, there is provided an articulated arm with vertical pivoting axes which is pivotally mounted on said shaft, this articulated arm carrying a vertically guided raising means engageable with said cover.

7 Claims, 6 Drawing Figures LAPPING MACHINE This application is a continuation of Ser. No. 781,212 filed Dec. 4, 1968, and now abandoned.

In my U.S. Pat. application Ser. No. 613,940, filed on Feb. 3, 1967 now U.S'. Pat. No. 3,456,393, issued July 22, 1969, there is described and claimed a machine for lapping plane surfaces in which the workpieces to be lapped are confined in rings placed on the bed of the machine and retained by arms provided with rollers which bear against the peripheral surface of said rings, the said arms being disposed in star formation and carried by a stepwise rotatable device, the angular extent of the steps of the motion of the device allowing the substitution of one ring by another while at the periphery of the bed. Furthermore, at least one plane, smooth table is disposed close to the periphery of the bed to permit the feeding of a ring to, and the withdrawing of a ring from, the bed by sliding.

This arrangement, which is intended particularly to facilitate the operations of loading and unloading the rotatable bed of the lapping machine, does however involve the machine operator in painful and tiring manual handling operations, particularly when small workpieces have to be lapped and which must be pressed into the rings against the lapping bed by heavy covers. These covers or loading plates, which serve to increase the pressure of the workpieces to be lapped on the lapping bed, have a mass appropriate to the particular lapping operation to be performed.

The present invention seeks to provide an improvement in the lapping machine claimed in said Specification, so as to considerably facilitate the handling of the loaded rings and of the covers.

According to the invention a surface lapping machine in which workpieces to be lapped are confined in rings placed on the rotatable bed of the machine, the workpiece or workpieces in each ring being loaded by a cover and the rings being retained on the bed by arms provided with rollers, the arms being disposed in star formation and forming a rotary assembly which is movable stepwise around a vertical or substantially vertical shaft disposed coaxially or substantially coaxially with the bed, while at the periphery of the bed adjacent to the stopping positions of the rings there is disposed a plane, smooth table permitting the feeding of the rings to, and the withdrawal of rings from, the bed by sliding, is characterized in that an articulated arm with vertical or substantially vertical pivoting axes is pivotally mounted on said shaft, which articulated arm carries a vertically or substantially vertically guided raising means adapted to be brought into engagement with said cover.

When the raising means is in its lower position, in engagement with the cover of a ring placed on the bed, the exertion of a force on the articulated arm enables the assembly of the cover and its ring to be slid onto the unloading table. After the cover has been raised, it can be moved by the articulated arm, with a minimum of effort, into a position above a ring supplied with workpieces to be lapped which is placed on the loading table. The cover can then be put in place on the ring and be returned from the loading table onto the bed by means of the articulated arm.

Preferably, the machine includes one ring more than the number of lapping stations on the bed and, in order to permit movement of the ringsby simple sliding, the unloading table is at a level which is slightly lower than that of the lapping bed and the loading table has a level slightly higher, an inclined ascending plane joining the unloading table to the loading table.

Operation of the machine according to the invention can be effected without any manual handling of heavy members; only the workpieces to be lapped, which usually are quite small and light, are moved by hand in order to be withdrawn from the rings after lapping, or placed in the latter for lapping.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which FIG. 1 is a schematic elevation of an improved lapping machine according to the present invention,

FIG. 2 is a plan of this machine taken at the level of the line IIII of FIG. 1,

FIG. 3 is a section, on an enlarged scale, taken along the line III-III of FIG. 2,

FIG. 4 is a view taken along the line IVIV of FIG. 3,

FIG. 5 is a section, on an enlarged scale, taken along the line VV of FIG. 3, and

FIG. 6 is a schematic elevation of the loading and unloading tables and of the lapping bed.

The lapping machine shown in the drawings comprises an annular table 2 carried by a base 1, which table surrounds a circular, flat and horizontally disposed bed 3 which rotates at slow speed.

The workpieces to be lapped are disposed, in contact with the bed, in cylindrical annular rings 4; they are pressed against the bed by the weight of heavy metal covers 5 which are engaged in the rings. The rings 4 are prevented from turning with the bed 3 by arms 8, disposed in star formation, which are carried by a central, vertical, tubular shaft 10 connected with an indexing mechanism. The latter allows the shaft 10, each time, to rotate in the direction of rotation of the bed 3, through an angle equal to half the angle substended by the centers of two rings at the center of the bed 3, i.e. through an angle of 60 in the example shown where the bed 3 carries three rings. On the shaft 10 there is freely pivoted a horizontal crank-pin 70 (see also FIG. 3). This crank-pin is carried by bearings 71 mounted in a socket 72 keyed on the shaft 10.

A tubular lever 74 of rectangular cross-section is hinged to the free end of the crank-pin 70 by means of bearings 73. The crank-pin 70 and the lever 74 constitute an articulated arm.

Against a vertical face of the lever 74 there is fixed an electric motor 75 which, via a reduction gearbox 76, drives a pinion 77 fixed to a cam 78. This cam comprises a lobe 78a which is arranged to actuate an end of travel reversing contact 79.

To the pinion 77 there is fixed the end of a chain 80 which passes over an idler pinion 81 mounted on a shaft 82 having its ends secured to the lever 74. A hub 83 (see also FIG. 5) is suspended from the chain 80, and on the journal 83a of this hub a thick disc 85 is rotatably mounted on bearings 84. The disc 85 is of generally truncated conical shape and it is provided with radial arms or pins 86.

A support 87 fixed to the lower face of the lever 74 is connected to the hub 83 by three compass links 88. The ends of the branches of these links are hinged respectively to the hub 83 and to the support 87. Since all the hinging axes are horizontal, the thick disc 85 is restricted to movement in a vertical direction relative to the lever 74, and whatever the movements of the articulated arms 70-74, it cannot oscillate with respect to these arms.

The length of the periphery of the pinion 77 is equal to the vertical travel of the disc 85, so that at each rise or descent of the disc, the pinion 77 rotates substantially one turn and the cam lobe 78a acts on the reversing contact 79. This reversing contact may be a simple circuit breaker in connection with an electrical rocker which changes its state on the occasion of each actuation of the said circuit breaker.

Each cover 5 has a crown 89 fixed to its upper face, which crown is provided with bayonet slots 95, the positions of which correspond to those of the pins 86. In order to maneuver the articulated arm, a handle in the form of a tongue 90 is provided at the extremity of the lever 74. This handle is associated with a button 91 for starting the motor 75 by means of a switch 92.

The machine includes an unloading table 57 and a loading table 58. As shown in FIG. 6, the table 57 is slightly below the bed 3 and the table 58 slightly above the bed 3. The unloading table 57 extends up to the edge of the table 58 which is provided with a ramp 93 extending down to the level of the table 57.

The device which has just been described operates as follows:

When the operator considers that the workpieces contained in one of the rings 4 are suitably lapped, he stops the machine with this ring opposite the table 57 and, by maneuvering the articulated arm with the handle 90, he brings the disc 85 above the cover of the ring 4 which is intended to be withdrawn from the bed 3. He then lowers the disc 85, the pins 86 of which come opposite the bayonet slots 95. The truncated conical shape of the disc 85 facilitates the engagement of the disc in the crown 89 and a very slight manual effort on the end of a pin 86 enables engagement of these pins in, or their withdrawal from, the bayonet slots 95.

Thus, by turning the disc 85, the pins penetrate to the ends of the slots 95, so that the articulated arm is secured to the ring 4 to be withdrawn through the intermediary of its cover 5. By moving the articulated arm, employing the handle 90, the ring 4 is then brought onto the unloading table 57 and, by pressing the button 91, the cover 5 is raised. This cover may then be moved into position on workpieces contained in a ring 4 which is waiting on the loading table 58. The bed 3 is then displaced one step, i.e. in this particular instance 60, so that the emplacement freed by the withdrawal of the ring 4 comes opposite to the loading table. By a procedure which is the reverse of the above described withdrawal procedure, a loaded ring is fed onto the bed 3 by means of the articulated arm.

It will be seen that, in the course of these operations, the operator never has to exert the physical force necessary to raise the covers which load the workpieces to be lapped. Furthermore, he does not even have to raise the rings, since, in order to transfer an empty ring which has just been unloaded on the unloading table to the loading table where it will be reloaded with workpieces to be lapped, it is only necessary to slide this ring on the surface of the table 57 and then up the plane 93 (as indicated by the position 4a of the ring shown in FIG. 6) in order to raise it to the level of the loading table 58.

ln order to feed a loaded ring onto the bed 3, the table 58 is brought into contact with the bed 3, after which the ring is pushed off the table so that it descends onto the bed 3. The table 58 is then moved back into the position 58a (see FIG. 2) so that rings which project slightly from the bed 3 do not interfere with the table during rotation of the bed.

lclaim:

1. A surface lapping machine in which workpieces to be lapped are confined in rings placed on the rotatable bed of the machine, the workpiece or workpieces in each ring being loaded by a cover and the rings being retained on the bed by arms provided with rollers, the arms being disposed in star formation and forming a rotary assembly which is movable stepwise around a vertical or substantially vertical shaft disposed coaxially or substantially coaxially with the bed, while at the periphery of the bed adjacent to the stopping positions of the rings there is disposed a plane, smooth table permitting the feeding of the rings to, and the withdrawal of rings from, the bed by sliding, characterized in that an articulated arm with vertical pivoting axes is pivotally mounted on said shaft, which articulated arm carries a vertically or substantially vertically guided raising means adapted to be brought into engagement with said cover; and, in which the vertical guidance of the raising means is provided by at least two compass links of which the planes intersect at the axis of the said raising means, the extremity of the upper branch of each compass link being pivoted to the articulated arm and the end of the lower branch being pivoted to means engageable with the cover, all the pivoting axes being horizontal or substantially horizontal.

2. in a surface lapping machine for workpieces comprising a rotatable circular horizontal bed, rings for confining said workpieces on said bed, a cover in each ring for loading said confined workpieces; a vertical shaft protruding at the center of said bed; a rotary assembly having arms provided with rollers and disposed in star formation for retaining the rings on said bed in fixed position, said rotary assembly being adapted for stepwise rotation about said vertical shaft and a smooth table level with re s ect to said bed adapted for the feeding of a ring to and the wit drawal of the ring rom the bed by sliding,

the combination of a first arm portion, one end of which is pivotally carried by said shaft and a second arm portion, one end of which is pivotally carried about a vertical axis at the end of the first arm portion; electro-mechanical raising means carried by the outer part of said second arm portion, adapted to be brought into and out of engagement with said cover: guiding means for rigidly ensuring vertical displacement of said raising means; and grasping means carried by the outer end of said second arm portion for manual operation of the whole arm.

3. A machine according to claim 2, in which the means engageable with the cover comprises a disc of truncated conical shape which is freely rotatable at the lower end of the raising means and which comprises pins at its periphery which are engageable in bayonet slots provided in a crown fixed to the upper face of each cover.

4. A machine according to claim 3, in which raising of the disc is effected by a chain fixed at one of its ends to the disc, which chain passes over an idler pinion and is fixed at its other end to a pinion driven by an electric motor.

5. A machine according to claim 4, in which the driving pinion is fixed to a cam controlling at least one end of travel reversing contact.

6. A machine according to claim 4, in which the driving pinion has a pitch circle length equal to the vertical travel of the raising means and the cam acts on the same end of travel contact at the upper and lower limits of the vertical travel of the raising means, the said end of travel contact being connected to a bistable electrical device controlling the direction of rotation of the motor.

7. A machine according to claim 4, in which the end of the articulated arm carries a maneuvering handle associated with a switch for supplying the electric motor.

Claims

2. In a surface lapping machine for workpieces comprising a rotatable circular horizontal bed, rings for confining said workpieces on said bed, a cover in each ring for loading said confined workpieces; a vertical shaft protruding at the center of said bed; a rotary assembly having arms provided with rollers and disposed in star formation for retaining the rings on said bed in fixed position, said rotary assembly being adapted for stepwise rotation about said vertical shaft and a smooth table level with respect to said bed adapted for the feeding of a ring to and the withdrawal of the ring from the bed by sliding, the combination of a first arm portion, one end of which is pivotally carried by said shaft and a second arm portion, one end of which is pivotally carried about a vertical axis at the end of the first arm portion; electro-mechanical raising means carried by the outer part of said second arm portion, adapted to be brought into and out of engagement with said cover; guiding means for rigidly ensuring vertical displacement of said raising means; and grasping means carried by the outer end of said second arm portion for manual operation of the whole arm.