US2305928A - Electrical control apparatus for strip feeding mechanism - Google Patents

Description

Dec. 22, 1942. F, M. Ll' l'TELL ELECTRICAL CONTROL APPARATUS FOR STRIP FEEDING MECHANISM 4 Sheets-Sheet 1 Filed July 17, 1940 Dec. 22, 1942.

F, M. LITTELL ELECTRICAL CO NTROL APPARATUS FOR STRIP FEEDING MECHANISM Filed July 17, 1940 4 Sheets-Sheet 2 JFZUem ZDI Dec. 22, 1942. F. M. LITTELL. 2,305,928

ELECTRICAL CONTROL APPARATUS FOR STRIP FEEDING MECHANISM Filed July 17, 1940- 4 Sheets-Sheet S F; M. LITTLELL 2,305,928 ELECTRICAL CONTROL APPARATUS FOR STRIP FEEDING MECHANISM Dec. 22, 1942.

Filed July 17, 1940 4 Sheets-Sheet 4 Patented Dec. 22, 1942 ELECTRICAL CONTROL APPARATUS FOR STRIP FEEDING MECHANISM Frederick M. Littell, Detroit, Mich, assignor to F. J. Littell Machine Company, Chicago, 111., a corporation of Illinois Application July 17, 1940, Serial No. 345,934

4 Claims. (Cl. 33-132) The invention relates generally to the feeding of strip material to punch presses and has particular reference to improvements in apparatus for controlling the feeding length of strip material as disclosed in my Patent No. 2,140,755 of December 20, 1938.

The apparatus of said patent provides novel means for controlling the feeding length of metal strip material and which accurately measures successive lengths of the material. The feed takes place at normal speed for the greater part of each length and at a reduced speed for the remainder of its length. By slowing down the feeding means before interrupting the drive to terminate a feeding cycle the shock and strain on the feeding mechanism and gearing is considerably reduced and overrun is lessened so that greater accuracy is secured.

It is an object of the present invention to provide a measuring device which will embody the basic principles disclosed in my patent above identified and wherein various units will be arranged so as to be completely accessible from the front of the box when the cover is open. In this connection the separable back cover heretofore employed is eliminated and formed as an integral wall with the base of the housing.

Another object resides in the provision of improved mounting means for the reverse drive motor whereby the same will be securely held in adjusted position within the housing while permitting removal of the motor in the shortest possible time in case of repairs and the like.

A further object is to provide improved clutch release mechanism embodying a direct acting rocking lever and a push type solenoid.

Another object is to provide an improved supporting bracket for certain units of the device having spaced bearings for journalling shaft means for adjusting the device and which may be operated from the front of the housing by a hand wheel located in position for easy access by the operator.

Another object of the invention is a novel design and arrangement of operating gears for lightening the moving parts, thereby reducing the momentum of these parts during reverse rotation to substantially eliminate rebound when said rotation is stopped.

With these and various other objects in view, the invention may consist of certain novel features of construction and operation as will be more fully described and particularly pointed out in the specification, drawings and claims appended hereto.

In the drawings, which illustrate an embodiment of the invention, and wherein like reference characters are used to designate like parts Figure l is a top plan view of the casing or housing for the measuring device of the inven tion;

Figure 2 is a front elevational view of the measuring device embodying the improved features of the invention with the cover for the housin I removed;

Figure 3 is a vertical sectional view taken substantially along line 3-3 of Figure 2 showing the improvements of the invention with the cover of the housing in place;

Figure 4 is a vertical sectional view taken sub stantially along line 4-4 of Figure 2 and showing in elevation the improved rocking lever with push type solenoid;

Figure 5 is a detail sectional view taken substantially along line 5--5 of Figure 3 and looking toward the automatic resetting switch;

Figure 6 is a detail view, parts being shown in section, of the gear unit whereby the operator may set the machine for measuring different lengths of strip material; and

Figure 7 is a diagrammatic wiring diagram showing the electrical circuit for the measuring device.

Referring to the drawings which show an improvement of the invention, the numeral it) refers to the housing or casing of the device, the same having a front cover ll hinged as at l2, a base l3 providing the main body portion of the housing and which body portion has formed integral therewith a back wall l4. As shown in Figure 1, the cover II is provided with a handle 15, whereby the same may be locked to the base 13 of the housing. Said cover plate is provided with a central opening l6 having a bevelled surface on which is provided marks or graduations l'l, representing the measured length of the strip material.

The device is mechanically connected with the feeding rollers of conventional feeding mechanism through the gear l8 fixed to the shaft [9 so as to turn therewith. The pinion 20 is likewise fixed to the shaft and the latter is suitably journalled for rotation by the bearings 2| (Fig;

4) mounted respectively in the front bracket 22 and the rear plate 23 forming part of the integral wall M of the housing. Below shaft IS the said front bracket 22 and plate 23 journal the shaft 24, the respective ends of the same being mounted by bearings 25. Said shaft carries the gear 26 having meshing engagement with the pinion 29 and which is accordingly driven thereby. Also said shaft is formed with a shoulder 21 which properly positions the gear 26, the same being mounted on the shaft so as to have independent rotation. The concentric recess in the gear 26 receives the roller drive hub 28 and the extending portions 39 of the collar release shell 3!, the said extending portions having interlocking relation with the roller drive hub. Hub 28 is keyed to shaft 24, whereas, the release shell 3'! is held to the shaft by a pair of spring pressed detents 32. rality of clutch fingers 33 which are actuated by the clutch collar 36 mounted on shaft 24 for axial movement. The clutch collar 36 has connection with the bifurcated ends 31 of the direct acting rocking lever 38 pivotally supported at 40 from the rear wall M of the housing.

An improved feature of the present invention resides in the provision of a push type solenoid 41 located in the lower end of the housing and having a piston rod 42, the end of which contacts the adjusting screw 39 on the depending end of lever 33. Accordingly, when the solenoid is energized the piston rod 42 is forced to move outwardly in a direction toward the right, Figure 4. causing movement of the clutch collar 35 in an opposite direction to actuate the clutch fingers 33 and disconnect the drive from gear E8 to shaft E i. Normally with the solenoid l! deenergized the clutch is operative to connect shaft 24 so that the same will rotate along with any rotation imparted to shaft [9. Rocking lever 38 is held in a position to maintain the clutch operative by the plunger 43 energized by spring M. The plunger and spring are housed within member 15 extending rearwardly from the wall it and which makes possible the removal of the parts from the member from the front of the housing. It is also possible to remove solenoid ii from the ront of the housing since the same is suitably supported from the rear wall by the supports 46, the solenoid being bolted thereto by the bolts 41. It is only necessary to remove bolts ll and the solenoid can be removed. With the solenoid out of the way it is possible to remove lever 38 and thus the plunger d3. Shaft 24 carries a pinion 48 located to the left of gear 26 and which pinion has meshing engagement so as to drive the main gear 59, which, in accordance with the invention, is formed of high tensile aluminum in order to materially lighten the gear and thereby reduce the impact when the gear is brought to rest at the end of each cycle of movement. Said gear 50 is keyed to shaft Figure 3, journalle-d at its right hand end by the roller bearings 52 supported by the inwardly directed hub portion 53 formed integral with the rear wall l 4 and having an end plate 52-.

The left hand end of shaft 39 is suitably supported by the main bracket 55 having the hub portion 56 for the purpose. Said bracket 55 is better shown in Figure 2, wherein it will be observed that the same is substantially L-shaped in front elevation, including a vertically extending portion bent at its upper end, Figure 3, for securement to the base l3 of the housing by the bolts ill. The laterally extending portion of bracket 55 is secured to the side wall of the housing by bolts 58 and this portion of the bracket is provided with bearings 59 which will be referred to later on in the description.

The forwardly extending portion of shaft 51 carries a bushing til which extends a short distance beyondthe cover -.H at oneend, whereas,

The shell pivotally carries a plu-- the rear end of the bushing carries a worm gear El. It will be understood that said bushing is journalled by hub portion 56 and that the same has rotation independently of shaft 5 l. The split collar 62 is secured to the end of the bushing projecting beyond the cover and serves to hold the bushing properly located on shaft 5|. Also fixed to the bushing so as to rotate therewith is a disc 63 which is located to the rear of and substantially closes the opening id. The only indicating mark appearing on the disc is a diamond or other distinctive symbol (not shown) which when positioned opposite a numeral of the indicia ll of the cover plate will indicate that the measuring device is set for controlling the feed of strip material-in lengths corresponding to the magnitude of said numeral. Shaft 5| is formed with a reduced outwardly extending portion 64 to which is secured pointer 65, the same being adjustable on the shaft as a result of the split collar formed integral with the pointer. The pointer has rotation in a clockwise direction, starting from the diamond on the disc, which represents the starting position, and continuing until the zero of the indicia I! is reached, whereupon the shaft and the pointer is returned in a counterclockwise direction to its starting point. This terminates one measuring operation by clearing the electrical circuit and places the same in condition for the operator to start another measuring cycle.

The clockwise rotation of shaft 5| and pointer 65 is accomplished by the drive from the measuring roll of the punch press which has operative connection with gear I8, the drive continuing through the gearing including the clutch to the main gear 50. The projection or lug 66, Figure 2, carried by said main gear is accordingly rotated from the starting position and caused to contact roller 61 carried by the lever of the slow-down switch 68 having contacts 69 and then roller '10 carried by the lever of the stop switch H having contacts 12 and 13, as will be understood by reference to Figure 2 and Figure '7. The slow-down switch is adjustable with respect to the stop switch by means of the bolts 68a and this switch when actuated reduces the speed of the feeding mechanism by cutting in the slow-speed winding of the drive motor for said mechanism. Actuation of the normally closed stop switch will open contacts 12 of said switch and simultaneously close contact 73, the two sets of contacts being illustrated in Figure 2. It will be understood that the arm of the switch is actuated when the roller 10 is cammed'by the lug or projectionGS. The switches are of the double-acting type and may be purchased on the open market.

When the contacts F2 are separated the circuit to the drive motor is broken and said motor stops as above described. Simultaneously therewith contacts 13 are-closed and this results in energization of the push type solenoid 4| and closing of the circuit to the return motor 14. Said motor returns the main gear 50 and pointer 65 to starting position, the same having a head portion 15 whereby the rotor shaft of the motor through suitable gearing drives the horizontally disposed shaft 16. The head portion at one end contains an overrunning clutch 71 which is associated with this end of shaft 76 and functions to prevent reverse rotation of the shaft. The end of shaft i5 extending beyond the head portion opposite the overrunning clutch has suitably mounted thereon a friction gear 18 which is driven by the shaft through the washers l9 to thereby rotate'the main gear 56 in a counterclockwise direction. As a result of the friction gear 18 the main gear 50 may rotate in a clockwise direction during which operation shaft I6 remains at rest.

Energization of the push type solenoid 4| actuates the rocking lever 38 against the tension of the plunger 43 to cause axial movement of the clutch collar 36 whereby the clutch is thrown out so as to disconnect the drive from gear IE to the main gear 50. Immediately upon termination of the feeding operation by separation of the contacts 12 of the stop switch it will be readily understood that contacts 73 are closed to simultaneously energize solenoid 4i and cause operation of the return motor i l. With the driveto main'gear B disconnected through the clutch it is possible for the motor to return said gear and pointer 65 to starting position. Said position is indicated by the resetting switch 80,'Figure 5, carried by the worm gear El. More particularly, the starting operation is indicated by shoulder 8| provided by the lug 82 carried by the main gear Efi. Said shoulder is adapted to contact the pivoted lever 83 which in turn actuates the resetting switch, the same having the plunger 84 for contact by the pivoted switch lever. Said lever is carried by block 85 secured to the worm gear i5! and the same is therefore adjustable together with the resetting switch 89 by rotation of the worm gear. In order to conduct the electric current to the resetting switch and at the same time provide for the rotation thereof the leads 8B and 81 have electrical connection with commutator rings 88 and 89 carried by member 90 fixed to the web of gear 61 and which suitably insulates the commutator rings from said gear. The bracket 9|, shown in Figure 4, provides brushes 92 and 93 which contact the commutator rings, thereby completing the circuit to the resetting switch.

As previously explained, the main gear 50 is driven inua reverse direction by the return motor 14 until the resetting switch 8:] is actuated. The switch breaks the circuit to the electric motor, thus stopping reverse rotation of the gear, and also breaks the circuit to solenoid 4|, deenergizing the same, whereupon the rocking lever 38 moves to initial position under the tension of plunger 43 to render the clutch operative and again establish the drive from the gear 3 to the main gear 50. In order to prevent rebound of gear 50 with respect to the worm gear 6| a rebound check is provided in the form of a lever 94 (Fig. 5), secured to gear 5i] and carrying roller 95 yieldingly biased by the coil spring 96 so as to contact with the cam surface of block 85.

A feature of the present invention resides in the journalling means provided for the operating shaft 98 whereby the worm gear 6! can be rotated by the operator for varying the measured lengths of strip material. The operating shaft carries a worm I60 which meshes with worm gear GI and said shaft is suitably journalled at its end adjacent said worm by the bearing 59 formed integral with and depending from the bracket 55. The other end of the operating shaft 98 is also journalled by an integral bearing 59 depending from bracket 55 and this bearing extends through an opening in the side wall of the housing and has a reduced portion 99, as better shown in Figure 6. The reduced portion is adapted to receive the gear unit indicated in its entirety by numeral Iill, Figures 1 and '2, the unit including a portion providing a split collar' I92 by means of which. the unit is clamped to the reduced end of the bearing 59. The portion of shaft 98 projecting within unit i0! is reduced in diameter for'receiving thebevel gear I04; which gear has meshing engagement with a similar gear )5 rotated by the indexing Wheel I66. When the operator rotates the indexing wheel the drive takes place through gears I05 and Hi l to the operating shaft 98 and from said shaft to the worm gear 6i. Accordingly, it is possible to vary the location of the resetting switch 86 carried by the worm gear and this has the effect of changing the measured lengths of the strip material. In this design the unit Hll is carried by the bearing .59 of bracket 55 and the same can be easily affixed thereto or removed. The bevel gears locate the indexing wheel me toward the front of the device and parallel with the front cover of the housing.

The bracket 55, having the bearing 59 journalling the operating shaft, constitutes a unit that can be removed from the housing without disturbing the other elements of the device. This is an important feature which makes possible economical maintenance of the present electrical control apparatus since in the event of a break-down it is only necessary to disconnect the pointer 65 and remove the'bracket 55 and practically all the other elements of the device are-easily accessible to the operator, and also removable from the housing. 1 For example, Worm gear 6! and the main gear 59 can be removed from shaft 5! and likewise said shaft can be withdrawn from its rear bearing 53. The location of the solenoid tl also makes possible its. removal from the open front of the casing and the operation can be effected by the removal oi the four screws 47. Also to completely carry out this aspect of the invention the return motor 14 is mounted in dovetailed guides Bill and 38, the guides being permanently secured to the base portion [3 of the housing. interposed between the dove-tailed guide Hi8 and the base of the motor is a removable guide member [09 held in position by the bolt HI]. In order to remove the motor from the open front of the housing the bolt HE] is loosened and the removable guide member we is withdrawn. In the present design attention is called to the fact that the motor is entirely free of the rear wall I4 of the housing, which design is made possible by mounting the overrunning clutch T! on the head portion 75 of the motor.

When it is desired to start the device to perform a measuring cycle the starting button H2, Figure 7, is closed to energize relay A, which results in the closing of contacts A1 and A2. Closing of the first mentioned contacts completes the circuit to the driving motor so that the switch button H2 can be immediately released. Contact A2 maintains the circuit to the relay closed through the normally closed contacts 12 of the stop switch. The motor runs at high speed since the high speed winding HSW is in circuit. When the slow-down switch is actuated the normally open contacts 69 are closed, energizing relay B to cause B1 to close and B2 to open. This cuts out the high speed winding and the low speed winding LSW is connected in circuit. Continued rotation of the main gear results in actuation of the stop switch whereupon the contacts 12 are opened and 13 are closed. The driving motor will stop and by closing contacts 73 the relay C is energized, closing contacts C1 and C2. The

former will complete the circuit through the normally closed resetting switch 80 and closing of contact C2 will simultaneously energize the push type solenoid 4| and start operation of the return motor 14. The main gear 50 will therefore be returned to its starting position and when the resetting switch is actuated this breaks the circuit to relay C and opens the contacts so as to deenergize the solenoid and stop the return motor. The parts are now in position to start another measuring cycle which can be initiated by the operator by pressing the button H 2, or actuation of the limit switch LS can be effected automatically by the punch press.

What is claimed is:

1. In a measuring device for controlling the operation of mechanism for feeding strip material, in combination, a housing having a normally closed cover, a rotatable member journalled by the housing, a drive including a clutch operatively connecting said member with the feeding mechanism whereby said member is rotated in one direction proportional to the feeding of the strip material, an electric motor for rotating said member in a reverse direction when the drive is disconnected by the clutch, a push type solenoid, a lever directly connecting the solenoid with the clutch and having a pivotal mounting on the housing at a point intermediate said parts, a spring pressed plunger yieldingly biasing the lever in a direction to maintain the clutch operative, whereby energization of said solenoid actuates the lever in an opposite direction to render the clutch inoperative and disconnect the drive to the member, and means releasably mounting the solenoid in said housing permitting ready removal thereof from the housing when the cover is open.

2. In a measuring device for controlling the operation of mechanism for feeding strip material, in combination, a housing having a normally closed cover, a rotatable member journalled by the housing, a drive including a clutch operatively connecting said member with the feeding bad mechanism whereby said member is rotated in one direction proportional to the feeding of the strip material, an electric motor for rotating said member in a reverse direction when the drive is disconnected by the clutch, a push type solenoid, a lever directly connecting the solenoid with the clutch and having a pivotal mounting on the housing at a point intermediate said parts, a. spring pressed plunger yieldingly biasing the lever in a direction to maintain the clutch operative, whereby energization of said solenoid actuates the lever in an opposite direction to render the clutch inoperative and disconnect the drive to the member, and independent means releasably mounting the electric motor and the solenoid in spaced relation in said housing permitting ready removal thereof from the housing when the cover is open.

3. In a measuring device for controlling the operation of mechanism for feeding strip material, a housing including a base portion having a normally closed cover, a rotatable member within the housing adapted to be rotated in one direction by said mechanism proportional to the feeding of said material, a shaft therefor, means journalling the shaft including a bearing formed integral with the rear wall of the base portion for receiving one end of the shaft, and a bracket releasably supported from the base portion and providing a bearing for receiving the other end of the shaft, spaced and aligned bearings provided by said bracket, a control shaft journalled by said spaced and aligned bearings independently of the housing, said shaft controlling the extent of rotation of the member between starting and stopping positions, and a gearing unit fixed to one of said bearings and operatively connecting with said control shaft.

4. In a measuring device as characterized by claim 3, wherein the gearing unit is located ex teriorly of the housing and said unit provides an indexing wheel for actuation by the operator.

FREDERICK M. LIT'I'ELL.

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