US2233312A

US2233312A - Grinding machine

Info

Publication number: US2233312A
Application number: US291589A
Authority: US
Inventors: James A Harrold
Original assignee: HERMAN POLLACK
Current assignee: HERMAN POLLACK
Priority date: 1939-08-23
Filing date: 1939-08-23
Publication date: 1941-02-25
Anticipated expiration: 1958-02-25

Description

` Feb.25,1941. AHA-RRQ@ y 2,233,312

GRINDING MACHINE Patented Feb. 25, 1941 UNITED STATES 2,233,312 Gammo MACHINE James A. Harrold, Clifton, N. J., assirnor of one- 'l half to Herman Pollack, Paterson, N. J.

Application August 23, 1939, serial No. 291,589

This invention relates to an improvement in lens edge grinding machines. I

An object of this invention is to intermittently rotate theV lens being ground and such rotary vl movement being imparted to the lens upon the l removal of the glass down to size governed by a pattern. This construction diiering from the present or generally accepted method for grinding lens wherein the lens and grinding wheel are both continuously rotating during the operation of grinding the lens down to size or shape.

In the present invention, the lens is held in contact with a continuously rotating grinding wheel until a desired amount of glass or ma- ]5 terial is removed whereupon the lens is rotated suilciently to present another surface to the wheel, and so on until the lens has been given a complete rotation in producing the desired shaped lens. A pattern is provided for governing the 20 amount of material to be removed. As each quantity of material is removed from the stationary lens, the pattern will be moved into ay position for establishing a circuit whereupon suitable mechanism will be actuated for causing gear trains to be operated for rotating the lens a sufli- Acient amount to bring a new surface in contact with the grinding wheel whereupon the circuit will be broken and the gear train stopped and a further grinding operation on the lens performed 30 by the grinding wheel.

The invention consists further in novel driving means for imparting intermittent motion to the carriage supporting the lens and pattern so that upon the removal of a portion of the glass 35 or material, composing the lens or other article,

is removed from the stationary lens held and supported by the carriage, the driving mechanism will be operated for imparting a slight rotary movement to the lens to bring a new surface into y 40 contact with the grinding Wheel, and upon the bringing of this new surface into contact with the grinding wheel, the'driving mechanism will be discontinued and the material of the lens removed, and upon the completion of this grind- 45 ing operation the driving mechanism will be again established and another cycle completed. In this manner a complete rotation of the lens will proand it is necessary to disengage the carriage and stop the rotation of the lens and for the operator to determine by hand, that is by"'feel, whether or not the lens has been ground to the proper shape and size and then causing the lens to be 5 again brought into engagement `with the grinding wheel for removing these rough or high spots that exist on the lens before it can be termed a iinished product. Whereas, with this invention, these objections are eliminated and upon one complete revolution or in some instances one additional turn at a regular speed would assure a smooth edge and the lens would be completed at onethird the usual time now required without the necessity of being observed by an attendant to insure that all uniinished portions or high spots have been removed from the lens.

The invention consists of certain novel features of construction and combinations of parts which will be hereinafter described and pointed out in the claims.

In the accompanying drawings,

Figure 1 is a detailed view partly in section of the automatic means or control for governing ythe rotation ofthe lens to be ground.

Figures 2 and 3 are horizontal sectional views of the clutch mechanism shown in Figure 1. Figure 4 is a perspective view of a standard lens grinding machine having a portion broken away l to better show the invention applied thereto.

Figure 5 is a View in side elevation oi a portion of such standard machines showing some of the parts broken away to illustrate the driving mechanism for the lens supporting carriage.

Figure 6 is a detailed view in elevation show- 35 ing the position assumed by the lens and pattern during .the grinding operation of the present invention.

This invention is capable of being applied and used in conjunction with the standard machines and for the purposes of illustration the invention has been adapted to a rimless edge grinder.

A portion of such machine as is believed sufficient for illustration has been disclosed -in the drawings and will now be described for the purpose of obtaining an understanding of the present invention.

Referring to Figures 4 and 5, the numeral 35 represents the machine base or bed upon which is mounted for reciprocatory movement a table 5|. An arbor 36 is mounted in suitable bearings 31 on the base 35. Power is transmitted to the arbor 36 through a pulley 38 mounted thereon and a belt 39 transversing the pulley, which' belt is connected to some suitable power supply, not

shown. Mounted on the arbor 38 is a grinding wheel or stone 48.

Table 5| is provided with two stanchions 52. Interposed between the stanchions and supported thereon for oscillation is a carriage consisting of

housings

56 and 51 connected together by a tubular member 55, the

housings

56 and 51 being connected by pivots or trunnions 53-54 to the stanchions. 52. .Journalled in the tubular member is a shaft 68 provided with gears -1|, 12 at each end which are located within the

housing

56, 51 respectively. A head spindle 11 is journalled in the housing 56 and is provided with a gear 15 which meshes with an idler gear 13 journalled in the housing and which idler gear meshes with the gear 1| of the shaft 68 whereby motion is imparted from the shaft 88 to the spindle 11. A tail spindle 18 is journalled in the housing 51 and is provided with a gear 16 which meshes with an idler gear 14 journalled in the housing 51 and which idler gear meshes with the gear 12 of the shaft 68 for imparting rotation from the shaft 68 to the tail spindle 18. The head spindle 11 and the tail spindle 18 are provided respectively with pad holders 80, 8| for supporting the lens material 82 to be ground. The head spindle 11 also carries a pattern 19 which will be g of a size and shape that conforms to the shape and size of the lens to be ground. Within the housing 51 is a yoke 89 which engages a collar 98 on spindle 9| mounted for reclprocation in the housing. Interposed between the spindle 9| and the shaft 18 is a thrust bearing 92. A lever extends through and is mounted on the housing 51 and is provided with. a cam 88 for actuating the yoke 89 for causing the pad 8| to be moved toward the pad for clamping the lens between the two pads of the shafts 11, 18. The movement of the lever 83 in one direction will cause the spindle 9| to exert pressure on the shaft 18 for reciprocating it for either clamping the lens in position between the pads 80, 8| or for releasing the lens from engagement with the pads.

A pulley 4| is mounted on a shaft 42 Journalled in the base 35 and power is transmitted to the pulley 4| from a pulley 48 on the arbor 36 through a belt 43. Motion from the shaft 42 is transmitted through the worm gear 44 thereof through a universal connection 45 to shaft I. Gear housing 61 is mounted on one of the stanchions 52 and has a shaft 65 journalled therein. The shaft is connected by means of a compensating means 10 with a disk 69 on shaft 68. The shaft 65 is provided with a helical gear 66 adapted to mesh with a helical gear 59 on shaft 58. Shaft 58 is journalled in a bearing bracket 68 which is pivoted to the stanchion 52 by means of a shaft 6I. A bracket 63 connected to` the gear housing 61 supports a cam shaft 62 which is adapted to be oscillated by means of the handle 62' for oscillating the bracket 60 in establishing engagement between the

gears

59 and 66. When these gears are out of engagement, the hand wheel 64 on the shaft 65 permits manual operation of the gear train 1|, 13, 15 and 12, 14, 16 for manually turning the lens and pattern.

Shaft 58 is connected to shaft 2 by means of a universal connection 58 and shaft 2 is arranged in alignment with shaft I, which shafts are capable of being engaged and disengaged through suitable clutch mechanism whereby intermittent motion may be impartedfrom the shaft 2 to the shaft 68 and gear trains.

The foregoing description is primarily based on the standard machine, and hence forms no part of this invention except insofar as thev drive mechanism is concerned with particular respect'- to shafts I and 2 and its related mechanism to now be set forth.

engaging the collar I2 and the other end xed to the sleeve 5 so that upon the rotation of the shaft I, the collar I2, sleeve 5 and clutch ring 3 all rotate as a unit.

Mounted on the lower end of shaft 2 is a sleeve or outer clutch member 6 which has a sliding engagement upon the shaft 2 through a key I6 carried by the shaft and a keyway or groove I1 formed in the sleeve. The lower end of the sleeve 6 is provided with a clutch ring 4 having an outwardly and downwardly tapering surface which is adapted to engage the balls 96 for retaining them in the cage. The balls 96 travel on the inner surface of the clutch ring 4 and ride in recesses I3 formed in the outer face of the clutch ring 3 on the shaft I. When power is desired to drive the shaft 2 and shaft I is rotating, the .balls 96 will be caused to travel in the recesses I3 where they will be impinged against the walls of the recesses and the inner f ace of the ring 4 for locking the clutch members together whereby the motion of shaft I will be imparted to shaft 2, Figure 3. Upon the raising or moving of the sleeve 6 upwardly, the pressure on the balls is released and the tension of the spring 1 is released causing the balls to -be moved to the position as indicated in Figure `2 or in free running position.

Loosely mounted on shaft I is a sleeve 9 which is supported thereon by the collars I2 and I4 xedly secured to the shaft I. the sleeve 9 are twoA parallel plates 2| provided with slots 34 fitting around the'sleeve 9. lThese plates are clamped together and about the sleeve '9 by means of clamping bolt 23 and their outer ends are connected together bly a transverse clamp bolt 24 similar to the -bolt 23. Connected to the plates are stanchions 26 by means of the bolt 24 and dowels 25. Pivotally connected to the stanchions are two parallel rods 21'hinged thereto by means of a pin 28. 'I'he other terminals of the rods 21 are connected to a trunnion collar l0 carried by the sleeve 6 o r outer clutch member, this collar I0 being held to the sleeve by means of a collar II. Mounted on the plates 2| is a cross plate 22 for supporting the magnet I8 by means of brackets 3| for the energizingcoil I9. An armature 28 is connected to'the rods or levers .21 by means of brackets 29. Magnet coil terminals 33 are mounted upon an insulated strip A32 carried by the plates 2| and suitably connected to the magnets I8.

The wires IIiIl-IiiI of the circuit lead from a suitable source through a transformer, rectifier.

The electrical circuit consisting of the wires |00|||I extending from the contacts 33'to the seat 84, is provided with a suitable transformer, rectifier and condenser. j

The sizer seat 84 is carried by an arm |82 connected to the hand wheel 85 which is supported massigv on' the base 6I. Suitable insulation |88 is interposedV between the seat 84 and arm |02.V The electric 'circuit fromV the terminals 88 extends to the sizer seat 84. one wire being connected to the seat 84 and the other wire to arm |82. The circuit is groundedon the machine as indicated at .I 84. The sizer seat 84 is mounted upon the table I and is capable of adjustment with respect to the pattern or former 18 on the shaft 11 so that as the former makes contact with the sizer seat 84, the electric circuit is established causing the magnet I8 to be energized and attracting the armature thereto. The movement of thearmature 20 into engagement with the magnet oscillates the rods 21 causing the trunnion collar I8 to force the outer clutch member 8 on the shaft 2 downwardly against the tension of the spring V8, interposed between the collar and end of shaft I, for establishing an engagement between the two shafts.

The axial movement of the outer clutch member 6 into engagement with the inner clutch member causes an engagement between the downwardly tapering surface on the inner face of the clutch member 4 and the balls 88 carried-by the cage 5, forcing the balls inwardly against the clutch ring 3 and causing them to roll across the circular recesses I8 against the pressure exerted by the spring 1 and wedging the balls between the rings Band 4 in a positive grip, as indicated in Figure 3. The shaft I which is rotating through its connection with the arbor 36, lpulleys 40, 4I andI belt 48, will now transmit this rotary movement to shaft 2 through the outer clutch member 6 which is keyed thereto. Therotation of shaft 2 will be transmitted to the gear 59 which is in mesh with helical gear 88 and the rotation of the gear 66 will cause power to be transmitted to shaft 65through the compensating

connection

68, 18 to shaft 68 of lthe carriage. The rotation of shaft 68 will` cause the gears 1l, 12 thereon to be rotated and motion will be imparted therefrom to the

gears

13, 14. This movement will be imparted to the lens 82 and former 18 causingv them to be rotated as clearly indicated in Figure 6. As soon as the lens 82 has been rotated sufficiently to again contact with the grinding wheel 46 andbringing a new surface tothe grinding wheel to be ground, the former 19 will have passed out of engagement with the sizer seat 84 thereby breaking the electric circuit and allowing the armature 28 lto become disengaged from the magnet and the outer clutch member 6 to move axially under the influence of the spring 8 away from the inner clutch member thereby declutching the shaft 2 from the shaft I and interrupting .the rotation of the

shaft

2, 68, 11 and 18.

f When outer clutch member 6 is moved axially inward or downward additional pressure is placed on balls due to the tapering form of outer clutch member 4. As shaft I is turning carrying 8 and 6 this additional pressure 'due to the lay of 8, causes balls 96 .to roll across circular recesses I3 carrying cage 5 with them, which is normally held in position shown in Figure 2 by spring 1, to the position shown in Figure 3, the engaged position. 'I'here are three sequences of action here that must be explained. Note Figure 2, balls 88 and ball cage 5 are held by spring 1 in a positionv change in position of balls 86 in ,recesses I8, and under no circumstances must balls be permitted to leave their respective recesses. The drag is between balls tending to mount the sides of recesses due to action of spring 1 but being prevented, by outer clutch member 4 as I. 8 and 6 turn and member 4 is stationary. As member 4 is moved inward or downward additional pressure is placed on balls due to taper of inner surface of member 4, the balls 88 then tend to roll down to center of recesses at which point magnet I8 has drawn armature 28 into full contact and exerts its greatest pull, balls must continue to roll until they are wedged between the opposite sides of recesses and outer clutch member 4 as Figure 3.

. As long as this downward pressure continues the clutch is engaged and driving its load. When the magnet releases it is to be noted that tapered inner surface of clutch member 4 tends to rise as pressure is released and spring 1 tends to return balls to their original position, see Figure 2. The clutch is engaged or operated without friction between outer clutch member 4, inner clutch member 3 and balls. Asclutch closes on balls there is no friction as balls are free to roll and they do roll until stopped solid as they wedge between

members

3 and 4.

As the carriage is pivotally supported upon the stanchions 62 by the trunnions 53, 54, this carriage is capable of oscillating to and from the grinding wheel 46 although it normally hangs substantially in a vertical position and "as the lens during the grinding operation is held against rotation by the stationary gear trains against the face of the grinding wheel, the weight of the carriage and the tendency for the carriage to move toward the grinding wheel holds the lens in position against the face of the grinding wheel. To insure of the lens being held against the face of the grinding wheel, a bracket 48 is connected to the housing 51 of the carriage, upon which is mounted a weight 48 adjustably supported on a rod 58 of the bracket 48. By positioning the weight 48 along the rod 58, it'can be readily determined the amount of pressure required for insuring the lens being held against the face of the grinding wheel 46 to obtain the desired cutting action. Naturally as the lens is ground down to size or to the shape desired, .there will be greater oscillation of the carriage as the former 19 contacts with'the seat 84.

The driving connection between shaft 2 and 68 may be disconnected whenever desired by simply operating -the handle 62' causing the c-am shaft 62 to osclllate the bracket 60 and causing the gear 58 to be moved out of engagement with the gear 86 whereupon 4the sli-aft 68 can be rotated `by means of the hand wheel 6-4 and through the train of gearing 13, 15, 14, 18, the lens 82 and pattern 18 may be adjusted or examined -to suit the wishes of the operator.

In .the operation of grinding the lens, which has been fabricated as prescribed by an optician, the proper pattern or former 18 is selected and mounted on the head spindle 11, and then the lens is clamped between the pads 88, 8 I, by shifting the spindle 18 vthrough the lever 83, cam 88 and yoke 88. Sizer hand wheel 85 is operated for setting the sizer seat 84 with respect to the former 18. The carri-age which may be elevated or swung by the handle 86 is now lowered allowing 'the lens to rest against the grinding wheel 46. During the preliminary assembly of the parts the gears 58v and y88 are generally out of mesh permitting the spindles 11, 18 of the carriage :to be operated through the hand wheel 64. However.

` as soon as the grinding operation is to be effected,

the

gears

59 and 88 are brought into engagement.

Upon .the rotation of the grinding wheel 48 and setting the lens against the wheel 48, the lens will be grounded until the sizer seat 84 and pattern 19 contacts.

The carriage is being moved to the vertical due to the removal of the material from the lens and causing the pattern 18 to be brought closer and closer'to the sizer seat, and upon the removal of the necessary quantity of material from the lens to conform to the shape of the pattern, the pattern will be brought into engagement with the sizer seat 84 and there wilibe no further grinding contact between the lens and grinding wheel. When the seat 84 and pattern 19 contacts, see Figure 6, an electric circuit is established, through the circuit between the seat and the magnet I8..

The energization of the magnet I8 causes .the armature 20 to be attracted and brought into engagement therewith, .this action causes the rods or levers 21 to be oscillatedon their pivot 28. The levers 21 will cause 4the outer clutch member 9 to be' moved axially of .the shaft 2, bringing thel slight drag of the balls 95 against the outer clutch ring 4 of the clutch member 8, but not sufficient to cause rthe clutch members to be engaged until .the clutch member 8 is moved axially under the influence of the levers 21, .to-bring it into a posiltion -to cause Ithe balls 98 to be moved inwardly into the recesses I8 of the ring 8. This movement of member 9, due to the rotation of shaft I and cage5 will cause the fballs 8 to ride across the recesses I2 'and exert a pressure between .the rings 8 and 4 sufcient to lock the two clutch members together. whereupon motion is imparted to shaft 2 causing it to rotate

gears

59, 66 and shaft 88. The rotation of shaft 68 will .transmit motion to the spindles 11-18 through the gear trains and thereby cause the lens 82 and former 18 to be rotated for the purpose of bringing a new surface of the lens into engagement with .the

grinding wheel. It is 4to be noted that when coni tact is made between pattern 19 and sizer seat 84 the lens isvout of contact with Ithe grinding wheel and no further amount of glass is being removed therefrom.

Referring to Figure 6, the lens 82 is shown with several of its peripheral faces completed or ground f to conform to the pattern 19, while the face against the wheel 48 is being ground and partially finished. The lower faces are still unground.

' This can be readily appreciated as the pattern and lens are rotated in aclockwise direction to bringnew surfaces into contact with -the grinding wheel. The sizer seat 84 has its outer face inv the presen-t instance curved substantially to the curvature of the grinding wheel 48, and it is val of contact of the lens with .the grinding wheel and the interval of contact of the pattern with .the seat 84. Thait is, the lens is ground duringthe period that contact is' broken between Ithe pattern 19 and seat 84 and until contact is again established between these

members

19 and 84. Therefore, there will be numerous engagements and disengagements between the seat 84 and pattern 19, in grinding each face of the lens, or such faces as correspond to .the faces of `the pattern 19.

The entire face is not removed at each engagement between the lens 82 and grinding wheel, but instead only a small portion, 'or so much of .the lens as can be presented .to the annular face o1' the grinding wheel. As a result. there will be numerous engagements between the' pattern and seat for stopping 4the grinding operation, because the lens will be out of contact with the Wheel' I when the pattern engages the seat 84. Of course. this engagement of .the pattern with the seat establishes the circuit, and power is .transmitted to the spindles 11-18 causing the pattern 19 and lens 82 -to'be rotated, but only sufficient to bring a portion of .the lens into engagement with the grinding wheel and the pattern out of contact the circuit andthe rotation ofthe spindles 11, 18,

of the carriage, the lens 82 and former 19 are now rotated to bring a new surface of the lens into engagement with the grinding wheel, .thereby elevating the carriage and causing Ithe contact between the pattern 19 and seat 84 to be broken. Substantially one or two .thousandths of an inch movement of the pattern 19 away from the seat will break the circuit and allow the magnet I8l -to release the armature 20. The outer clutch member l5 will now automatically move axially away from the inner'clutch member by the combined action of spring 8 and the wedge formation on the inner surface of outer clutch ring 4 due to the tendency of the spring 1 to return the balls 96 of the cage 5 to the opposite side of the circular recess I3 as indicated in Figure 2. The pressure on the balls is relieved upon the movement of the outer clutch member away therefrom and therefore the clutch members. are released from engagement with each other and the balls and cage 5 are again returned to free running position as indicated in Figure 2.

disengaged through a one way or over-running clutch, insuring practically an instantaneous engagement and disengagement of the shafts, without causing the spindles 11 and 18 to' be overdriven in advancing the lens blank in contact with the grinding wheel, but only causing a movement of the blank suilicient to present a new surface to the grinding wheel. When the clutch is disengaged, and the pressure on member 6 is relieved by the magnet, the balls 96 are in the position indicated in Fig. 2, there is a slight drag as the cage 5 turns and' ring member 4 is stationary. This prevents any backing up of the spindle gear train due to any friction'between grinding wheel and lens blank, when lens blank is first set against grinding wheel. This drag is insufilcient to turn gear train and spindle and tail spindles and having a slidable clutch ele-- 55 posed between said clutch elementsl of said driven n assembly even when lens blank is'raised off of grinding wheel.

The lens is now again held stationarily in contact with the grinding wheel as the gear trains will act as a-brake against the rotation o f the spindles I1 and 1l. This cycle of operation is continued until all of the material of the lens has been removed in conformity with the shape desired by the pattern employed. One complete turn or revolution of the lens is suilicient generally to remove all of the glass and bring the lens downto proper size and shape. Of urse. as the last amount of glass is removed the pattern and seat will again contact and the circuit will be established causing the clutch to lbe engaged between shafts l and 2 so that the spindles 11, Il are again rotated and will cause the lens to be rotated. This rotation of the lens along with the rotation of the grinding wheel insures the removal of any'superiiuous glass that may affect a true shape or size of the lens. One revolution of the lens under this condition is Agenerally sumcient. Oi course. if there are any hish spots left on the lens after the first revolution, the lens will contact with the grinding wheel and raise the carriage and break the circuit sothat the lens will dwell or stop at this high spot until this material has been removed when the lens will immediately begin to rotate. The continuous.

turning or rotation of the Alens with respect to the grinding wheel indicates to the operator that the lens is completed. With this method of removing the material and the forming of a lens production time is reduced from one half to one third compared with the general methods of thepresent time. This method entirely eliminates the constant stopping of the machine or carriage where the lens is continuously driven for the operator to examine the lens by feel to determine whether a suilicient amount of lens has. been removed.

What I claim is: l. In a lens grinding machine having a continuously driven grinding wheel and intermittently rotated head and tail spindles. said head and tail spindles supporting a pattern and a lens blank to be operated upon by said grinding heel, means including a continuously rotative ving shaft and a driven shaft for imparting rotary movement to said spindles and lens blank, said driven shaft drivably connected to said head ment connected thereto, a clutch element xed on said drive shaft, spring controlled ball means loosely mounted on saiddrive shaft and interanddrlve snaftsandnormallymaintainingsaid clutch elements declutched, electro-magnetic means for exerting pressure on said slidable clutch element of said driven shaft for forcing it into engagement with said means and the other able clutch element whereupon said ball means will automatically cause the clutch .eiements to be declutched and interrupting the movement of said lens blank.

2. In a lens grinding machine having a continuously u'riven grinding wheel and intermittently rotated head and tail spindles, said head and tail spindles supporting a pattern anda lens blank to be operated upon by said grinding wheel, means including a continuously rotative driving shaft and a driven shaft for imparting rotary movement to said spindles and lens'blank, said driven shaft drivably connected to said head and tail spindles and having a slidable clutch element connected thereto, a clutch element fixed on said driving shaft, spring controlled ball means loosely mounted on said driving shaft and interposed between said clutch elements of said driven and drive shafts and normally maintaining said clutch elements declutched, electromagnetic means for operating said movable clutch element, an electric circuit associated with said magnetic means, contact means in said circuit adapted to be intermittently engaged by said pattern for causing the magnetic means to be energized and deenergised. said magnetic means upon being energized exerting pressure on said movable clutch element for forcing it into engagement with said ball means and the other clutch element for causing said clutch elements to be clutched and imparting rotary movement to the lens blank and pattern. said pattern upon rotation being disengaged from said contact means and thereby breaking the circuit and deenergizing said magnetic means, said magnetic means upon being deenergized relieving the pressure on said clutch element whereupon said ball means will automatically cause the clutch elements to be declutched and interrupting the movement of said lens blank and pattern.

JAMES A. HARROLD.