US2376947A - Last lathe - Google Patents

Description

y 1945- E. TOPHAM 2,376,947

' I LAST LATHE Filed Sept. 4, 1943 3 Shee'l :sSheet l I [72 van tor Laure rncc E Topham U B3 hi Attovhey May 29, 1945.- E. TOPHAM LAST LATHE 3 Sheets-Sheet 2 Filed Sept. 4, 1945 May 29, 1945. I... E. TOPHAM LAST LATHE I Filed Sept. 4, 1945 3 Sheets-Sheet 3 Inventor Laurence ETopham B i Attorne Patented May 29-, 1945 UNITED v STATES PATENT. OFFICE 2,376,947 LAST LATHE Laurence E. Topham, Wenham, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J a corporation of New Jersey Application September 4, 1943, Serial No. 501,276

(c 1.142-;-1-5 as shown, is, driven from the ,feed screw,

3 Claims.

This invention relates to last ,lathes of the type shown in United States Letters Patent No. 2,072; 228, granted March 2, 1937, upon application of L. E. Tophamet al., and is particularly concerned with the improvement of such lathes in respect to the accuracy of the results obtained when rately inamachine of this type, and the patented machine was designed to overcome the length grading errors which had previously occurred when using a single model wheel to control the cutting of lasts of more than one size from a given model. This was accomplishedby s0 shifting the mounting of the model wheel that the leading edge of the model wheel, instead ofthe front point thereof, would come to the length grading .center for the model wheel side of the machine when the corresponding portion of the cutter reached the length grading center for the cutter side of the machine. This producedcorrect overall length but caused an error in the width rading which had not previously existed, when the front points of th model wheel and cutter were correlated, with the result that the faces of the two last parts which abut at the joint in the last were not identical in size and shape and, consequently, the outer surfaces of the last parts would not be flush at the joint.

It is a primary object of the present invention to provide a last lathe of the type underconsideration in which graded foreparts and heel parts of two-part lasts can be produced with accuracy in respect to overall length without sacrificing accuracy in width grading and identity of the'abutting faces of the last parts at the joint.

With this object in view, I correlate the front point of the model wheel with ,theanalogous point on the cutter, thus producing the abutting faces of the two last parts of the same size and outline so that they will match perfectly, and correct the error in the overall lengths of the last parts by providing means for automatically modifying the length grading factor during the cutting operation by an amount just sufiieient to cancel the said error. In the embodimentillustrated herein, I employ cam operated mechanism for shifting the length grading handle,

with which the lathe shown in the aforesaid patent is provided, progressively as the cutting of the last part proceeds, the cam being so designed that the right amount of compensationis effected which effects translatory movement of the cutter carriage, through a reduction gear of such ratio that the .cam does not make more than one revolution during the traverse of the cutter .over the longestblock to be cut.

Another object of the invention is to provide mechanism which will grade up .or down with substantial accuracy two or more sizes, instead of only one size, each way, while using. the

I to grade up or down only one /2, size while using a given model. wheel.

This .object is readily accomplished by proper design of the aforesaid cam, by which ,any re quired magnitude .of correction of the length grading error can be obtained at any stagein the cutting operation and can. be distributedlengthwise of the'last part as desired.

The length grading error which the present mechanism is designed to correct consists in over grading"? i. e., when grading up, without changing model wheels, the machine withoutthe present invention produces a last part which is too long, and when grading down from the model it producesa last part which is too short By my novel compensating, mechanism the effect of the grading mechanism in the lathe may be progressively -diminished, while thecutting of the last part proceeds, by an amount sufficient toneutralize the overgrading effect of using a model wheel which is too thicker too thin. The cam may be so designed as to modify the grading factor to anydesired degree and, consequently, toeliminate the over grading error through a or more sizes up and down from the model. I I 1 Ihese and other features of the invention, comprising certainnovelcombinations and arrangements of parts, will. be apparent from the following description of a preferred embodiment of, the invention shown in the accompanying drawings, in which,

Fig. l is a view in elevation of the lefthand end of the machine, illustrating the novel apparatns of the present invention;

. 2 is .a view in front elevation of the lefthand portionof the machine:

Fig. 3 is a plan view, showing the essential regardles of the length of the model. The cam, to features oft rganization;

The invention is illustrated as applied to and shaft 68 is journaled in stationary bearings 18,

embodied in the lathe of Letters Patent No. I

2,072,228 hereinbefore referred g torg Reference I I may be made to that patent for a 'more complete showing of details of the lathe structure which are not modified by the'present invention. In the" 1 following description reference numerals in pa rentheses refer to analogous parts in the machine shown in the patent. I l

The machine has a main frame l (ID) with longitudinal slideways on which slide a cutter car'- 18 supported by the machine frame.

The ratio of the gearing 58, 54 is three toone and the said gearing constitutes a reduction gear between the feed screw 16, which effects translatory movement of the cutter carriage l2, and the cam 82. The pitch of the screw I8 is such thatthe cutter carriage is advanced one inch durr ing each twenty degrees of rotation of 'the cam riage l2'(l8) and a model wheel carriage l4 (l8 These are driven by a rightand left-hand screw I6 (28) which turns in the direction indicated by"? the arrow in Fig. 1 and engages nuts mounted in the carriages l2 and l4. The nut mounted in the model wheel carriage; I4 is provided with gear teeth engaging arack I8 (28) which is used for length grading purposes; j i

The model Wheel carriage carries a model wheel 28 (16) mounted in a holder 22' affixed to. the 7 carriage and the cutter carriage carries a cutter I 24 (18) by which the last block being turned is shaped.

The model 26 and theblock 28 aremounted to face in opposite directions on the axis 30 (14) about which they rotate when a' block is being cut. The length grading mechanism is best shown and, consequently, eighteen inches during one 'c'omplete revolution of the cam so that the cam does not have to make more than one revolution ."during the-traverse of the cutter over the longest 'block'to'bei cut. I

" f-A1; .the right-hand end or the arm 14, and ier- "erably integral" therewith, is a cam-slotted plate 88 (Fig.2) having, three slots 82, 84, 86 therethrough' The plate 80 is located directly behind the :length grading handle 52 which contains a spring;pressed pin 88v having a knob 911 by which the pin maybe pulled outward against the ten: sionfof the spring. When the knob is releas'ed the springpresses'the pin inward toward tlie plate in Fig. 3. The length-grading is effected by moving the sliding rack I 8, which turns the nut in the model wheel carriage l4, and this .movement of the rack is accomplished by a block 32 (I H!) which is pivoted to the rack and slides on aninclined guide 34 (I I2) as the carriage I 4 moves toward the right or left, carrying the rack l8 with it.

The guide 34 is mounted on a plate 36 (H4) pivoted at 38 onthe frame, I and is angularly adjusted by a gear segment 48 (I I8) pivoted at. 42 on'the frame and linked to the plate 36 at 44, 46. The segment is adjusted by a worm 48 on a shaft 50 operated by a length gradinghandle 52, shown in Figs. 1 and 2. All of the foregoing is substantially as shown and described in the aforementioned Letters-Patent. In the patentedmachine adjustments are made manually for grading up or down from the model by turning the length grading handle 52 toward theleft or right, as the case may be, the handle then being locked inadjusted position and left untouched while a last block is being turned.

For the purpose of the present invention it is I joumaled to rotate freely on a stationary stud 60.

mounted on the machine frame I!) in position for the gear to mesh with. thepim'on 54. Keyed to 80 and if Ith'efpin is moved intojregister' with'any one of the slots 82,84 86ft will enter the same 'From' an in'spectionjof Fig. Z it maybe s "n that the not 82 and as are,ee di sedjthatifth plate 88 is swung about the aidsof I the shaft fi il While the pin 88 is in one of'Said Slots v grading handle will be swung abontltheax s of 1e shaft 50, turning that shaft and r'nodifying the grading effect by shifting the inclinedguid 4 The slot 84 is so disposed that it is appro gima ey concentric with the shaft 68 and if the pin 88"b'e engaged inthis slot, which is its'correc't position for zero grade, the swinging of the plate 80 will have no appreciable grading or grade modifying effect. g I 7 As in the patented machinaa disk 92 is secured to the front end of .the length grade ad-' lusting shaft 50 and the length grading handle 52 is carried by a crank arm 94journaled loosely upon said shaft. A binding screw 96 passing through an arcuate slot 98 in the disk 92 is threaded into the end portion of the crankv arm 94 which is opposite to the handle 52 and serves normally to clamp the crank arm firmly to the disk, while permitting relative angular adjust ments to be made if required. g

From the foregoing it will be apparent that when the feed screw I6 is rotated to impart translatory movement to the cutter and model wheel carriages l2 and M the cam 62, which is driven by the feed screw, will be rotated and that the cam slot plate 80 will beswung about the axis of the shaft 68. If the in 88 is in either of the-slots 82, 86, thelength grading handle 52 will be turned toan extent and in a manner determinedby the shape of the cam path in the cam 62, instead of said length grading handle remaining immovable as it would do if it were inserted in'one or the other of holes I 88, [02' in a stationary disk I04 with which thepatented machine is provided. -The model wheel assemblies each comprise a model wheel 20 mounted in an individual holder 22 and are so designed that the front points of all model wheels will come to the length grading center-for the model wheel side'of the machine when the gear 58, to rotate therewith on the stud'BfLis a cam 62 which is engaged by a cam roll 64 upon the upper end of a cam lever 6S.

The, lever 66 forms, a part of a rigid rocke member comprising said lever, a shaft68, a bar 18, and a casting 12 which, as shown in Fig. 2, extends laterally in the form of an arm I4. The

' the machine.

the correspondingpoint of the cutter come's to the length grading center for the cutter sideof This is. partially shown diagram-' matically in Fig. 4 wherein 20A and 20B indicate two model wheels of widely different thicknesses, both being shown in neutral position with their front points on the axis 30 of the model at'th'e length grading center G for the model side of themachine as they are when the corresponding point of the cutter 24 is at the length grading center G for the cutter side of the machine.

Since the machine is so constructed that when the parts are in this position the pivot of the block 32 and the pivot 38 are collinear and adjustment of the length grading segment 40 will cause no movement of the rack l8 and the nut operated said carriages and efiecting translatory movement thereof, power driven means for grading up and. down by changing the relative movement of the model wheel carriage and the cutter carriage, including manually operated means for setting the grading means for different grades, a rotary cam geared to the feed-screw, and com nections between the camand the grade setting means whereby the setting of the latter is automatically changed within a selected grade during movement of the carriages.

2. In a last lathe, a' cutter carriage, a model wheel carriage, a rotating feed vscrew engaging said carriages and effecting translatory movement thereof, power driven means for grading up and down by changing the relative movement of the model wheel carriage and the cutter car-=- r riage, including manually operated. means for Setting the grading means for difierent grades,

1 mechanism geared to the feed screw, and con-v nections between saidmechanism and the gl'ade setting meanswhereby the settingof the latter is automatically changed within a selected during movement of the carriages.

3. In a last lathe, a cutter carriage, a model wheel carriage, a rotating ,feed screw engaging grade said carriages and efi'ecting translatorymove ment thereof, power driven means for grading up and downby changing the relative movement of the model wheel carriage and the cutter carriage, including manually, operated means for setting the'grading means fordifierent grades, a rotary cam, reduction gearing connecting the cam to the feed screw whereby the feed screw makes a plurality of revolutions during one re volution of the cam, a cam lever in cooperative engagement' with the cam, and connections between the cam lever and the grade setting means whereby the setting of the latter is automatically changed within a selected grade during the move ment of the carriages occurring during one revolution of the cam.

LAURENCE E. TOPHAM.

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