US2510401A - Machine for testing snap and recovery of sheet material - Google Patents

Description

June 6, 1950 c. E, JOHNSON 2,510,401

, .MACHBIEFOR TESTING SNAP AND RECOVERY I .OF SHEET MATERIAL Filed Dec. 22, 1947 3 sheets sheet 1 Ihwentot CHARLES E. JOHNSON 31! f v I (Ittomeg June 6, 1950 A c. E. JOHNSON 2,510,401

MACHINE FOR TESTING SNAP AND RECOVERY 0F SHEET MATERIAL Filed Dec. 22, 1947 3 Sheets-Sheet 2 3nventor CHARLES E. JOHNSON 0 Gttorneg June 6, 1950 c. E. JOHNSON 2,510,401

- MACHINE F TESTING SNAP- RECOVERY Y SHEET MATERI I Filed Dec. 22, 1947 a She'ets-Sheet s Fl G. 6 i

3nnentor C HAR LES E. JOHNSON Gttomeg Patented June 6, 1950 MACHINE FOR TESTING SNAP AND RECOVERY OF SHEET MATERIAL Charles E. Johnson, St. Paul, Minn., assignor to Brown & Bigelow, St. Paul, Minn.

Application December 22, 1947, Serial No. 793,260

6 Claims.

This invention relates to a paper testing machine designed to test the snap and recovery of paper stock on repeated bending of the same.

Heretofore, there have been a number of paper testing machines, such as Mullen tester, tear testers and stiffness testers which measure the specific properties of the paper stock or plastic sheet materials. However, I have developed a machine adapted to test the snap and recovery of paper when it is subjected to repeated bendmgs. testing the material used in making playing cards where itis essential that the cards be of a high quality wherein they will withstand considerable bending and where the snap of the card is important and where the cards are subjected to severe use.

With my machine I have found that the snap and recovery of the paper (especially paper card stock) can be conveniently measured. It is a feature to provide means for accurately measuring the snap of the card supported in my machine as well as measuring the recovery after the card is snapped a predetermined number of times, and thus the durability of the card may be determined by my machine.

My machine is designed to support a piece of paper or other material which is bent through a fixed but variable angle under constant speed, and upon its release it exerts a force on a hammer, which force is transmitted to a steel ball mounted on an inclined plane between guide rails.

The snap or recovery of the paper is measured in work units as a product of the weight of the steel ball and height to which it rises on the inclined plane. For convenience, the metric system of measuring work is used, but any other system can be used. In the metric system, the weight of the ball is in grams, and the height to which the ball rises is in centimeters.

A feature of my machine resides in providing a base frame upon which an electric motor is mounted. The motor is adapted to drive a transmission with a gear reduction means therein, and the transmission in turn drives the work arm which engages the card supported in the machine and bends it over a given period releasing the free edge of the card when completely bent, permitting it to snap back against a cylinder-like supported hammer which, in turn, strikes a steel ball to drive it up an incline to measure the degree of snap.

It is also a feature of my machine to provide a means for gripping the lower edge of the card to firmly hold the card in place while it is being My machine is particularly adapted to tested. This card gripping means may be released to free the card from the machine and to permit a new card to be inserted into the gripping means.

I also provide a hand operated means for the work arm which bends the card before it is released in testing the snap of the same. I have found that the motor operated means for the work arm is very satisfactory, because the work arm can be timed to rotate a predetermined number of times during a certain period; whereas, the hand operated means must be gauged by the skill of the operator.

A further object resides in providing an alternative form of snap tester wherein a simple pendulum is employed for testing the degree of snap of the paper or cards. In this form, the pendulum hangs from a bearing having the least possible friction to permit the pendulum to swing freely when struck by the card. A gauge is provided which indicates the degree of movement of the free end of the pendulum, thereby registering the work done by the paper or card when snapped against the pendulum. In this form, the work done by the paper is measured by the weight of the pendulum and the distance the center of gravity of the pendulum moves vertically.

Further objects and features of my testing machine will be clearly defined in the specification and claims.

In thedrawings forming a part of this invention:

Figure 1 is a side View of my testing machine 7 showing the housing for covering the working parts removed.

Figure 2 is a rear side view of my testing machine with the housing enclosing the Working parts shown in dotted outline.

Figure 3 is a front end view of my testing machine.

Figure 4 is a rear end view of the same.

Figure 5 is a diagrammatic work diagram.

Figure 6 is a plan view of my machine.

Figure 7 is a section on the line l--'! of Figure 6.

Figure 8 is a section on the line 8-8 of Figure 3.

Figure 9 is a section on the line 9-9 of Figure 8.

Figure 10 is a section on the line lfi|ll of Figure 9.

Figure 11 is an alternative form of snap tester in the pendulum type showing a diagrammatic side elevation of the same.

My machine A is designed to test the snap and recovery of paper stool: and other sheet material where it is desirable to determine the degree of snap in the material as well as the durability of the same which is guided by the recovery after the material has been subjected to a series of predetermined number of bendings. It is desirable that a machine of this character be of a simple construction; and therefore, I have designed the machine With a base H3 on one end of which I mount an electric motor H. The motor II is adapted to operate the transmission 3 which is illustrated diagrammatically and wherein a series of reduction gears are employed to transmit to the driving belt 12 a constant speed of a predetermined nature to drive the pulley is accordingly. Mounted upon the base l are a pair of upright brackets Hi which are adapted to support the bolts I5. The bolts 15 support the bracket it to one of the uprights l4. Bracket arm I! extends from the opposite upright 14 to support the other end of the shaft l8 adjacent the pulley 13.

The card or paper C to be tested is adapted to be held by the spring urged clamping "bar l9 with the lower edge of the card resting on the shelf of the mandril 2! over which the card is adapted to be bent on the upper arcuated end 22. I provide a work arm 23 carried by the shaft i8, the free end of which travels around in a circle. The arm 23 adjustably carries a Work rod 24 which may be adjustably positioned in the free end of the arm 23 by the holes 25 formed in the free end of the rod 23. The work rod 24 is adapted to contact the end of the card C projectin above the arcuated surface 22 of the mandril 2i. Thus, the work rod 24 travels around the axis of the shaft L8 in the orbit indicated by the dotted line 26 shown in Figure 8. Each time the rod 24% rotates past the upper end 22 of the mandril 2!, the card C is bent over the mandril, and when it is released from the rod 24, the card C will snap back to assume its original position if the card has sufficient snap to do so. As the card snaps back, it strikes the projecting tip 2'! of the hammer 28 causing the hammer to strike the ball 29 and force the same up the inclined track 30 and thereby indicate the degree of snap effected by the card C in assuming its original position held against the mandril 2.! by the clamp IS.

The track 30 is provided with gauge indicia 3.! formed on either side of the track so that a reading may be observed by the operator on the gauge indicia 3| indicating the distance that the ball 29 travels up the track 30 after the card C snaps against the hammer 2 8. The hammer 2 8 is mounted on the upright arm 32 so that the hammer will swing freely each time the card C snaps against the same.

The degree of snap is indicated by the indicia 31 along the track 30, and the number of snaps may be counted by the operator so that the snap may be determined by the resistance of the card to be snapped a predetermined number of times by the snap tester A. It will be apparent that the card being tested will not ordinarily recover completely from each snap, and the card may become weaker the more it is snapped so that it will not recover with the same degree of snap that it does on the first snapping operation. In this manner, the operator may be able to determine the snap or resistance to bending of the article placed in the snap tester for observation.

The table 33 in which the track 38 is formed is mounted adjustably to the bracket {'6 which extends on one side of the table 33 and down to the pivot point 34 The pivot point 34 is mounted on one of the upright brackets it. This mounting of the table 3?: permits the Work rod 2 a to rotate under the table and around the Work mandril 2!. The pivot point of the bracket 16 is supported by one of the bolts l5, and I provide gauge indicia 35 along an arcuated lower edge of the bracket IE (Figure 8) which may be adjusted in relation to the pointer 36 to indicate the degree of slant at which the table 33 is adapted to be set on the arm M.

It will be further apparent that the operator can gauge the setting of the incline of the table 33 by the gauge indicia 35, and then by movements of the gauge indicia 3! the operator can take his readings of the travel of the ball 29 up the track 33 so that he can accurately record each snap of the card C and thereby determine the snap or the resistance of the card to snap or bending action.

The snap or recovery of the paper or card C is measured in work units as the product of the weight of the steel ball 29 and the height to which it rises on the inclined plane. AS an example, the metric system of measuring work is used, but any other system can be employed. In the'metric system, the weight of the ball is in grams and the height to which the hall rises is in centimeters. The height 1-1 to which the ball/rises is calculated as the product of the distance D along the inclined plane and the sine of the angle at which the plane is inclined. Thus, H :73 sine a, as illustrated in the'diagram shown in Figure;

The paper tester machine A is provided with a release lever 31 having a cam end 38 which is connected by the rod 39 and the lever 49 to the clamp IS. A coil spring 4| normally holds the clamp E9 in clamping position as illustrated in Figure 8. When the free end of the lever'3 9 is moved in either direction, the spring 4| is compressed, and the lever 48 pulls the clamp r9 into a released position as illustrated in Figure .9. The clamp bar 19 may be covered with a rubber tubing to increase the eificien-cy of the bar to hold the sheet C in position While it is being snap tested over the mandril 2|. The lever 31 is held a ainst the side of the bracket plate l6 under the tension of the spring 4|, and it is prevented from rotating by the guide pin 42.

Paper testing machine A may be operated by hand through the hand lever 43 which is .connected to the pivot l8 and which permits the operator to rotate the arm 23 causing the rod 24 to come in contact with the paper or card, C and bend it over the mandril 2|.

It will be apparent that another simple iorln of my testing machine may be carried out by a pendulum device which is positioned in a manner to be struck by the card when it snaps back after having been bent over the mandril 2] and which I have illustrated diagrammatically in Figure 11. In this form of the paper testing machine A, the pendulum 44 hangs on needlepoint, jewelled bearings 35 so that the pendulum may swing very freely. The card C is held by the clamp H3 at its lower end, so that the free upper end of the card may be bent over the surface 22 of the mandril 2! in the same manner as is illustrated'in the, figures heretofore described and more particularly in Figure 8. Then, when the card is released, it will snap against the free end. of the pendulum 44 causing the same to move toward the dotted position thereof as illustrated in Figure 11. The pointer 46 on the free end of the pendulum will indicate along the gauge indicia 41 the movement of the pendulum as it is struck by the paper or card C. Thus, the operator'will be able to observe each movement of the pendulum and thereby record the snap recovery of the paper or card, together with the degree of resistance of the paper or card to this test. The work done by the material C is measured by the weight of the pendulum and the distance the center of gravity of the same moves vertically. For example, Work=Wd where W=weight of pendulum.

In either the machine A or A I am able to obtain very accurate recordings of different characters of paper, cardboard and card stock which is used for playing cards wherein the degree of snap of the card is essential to wearing qualities of the same under extreme use.

My paper testing machine A can be used for measuring the snap Of paper or plastic sheet material after one or any number of bends. The difference in snap after one bend and a number of bends indicates the fatigue or resiliency of the stock. The actual values for playing cards are given in the following table to show the dinerence between good and poor playing card stock from the standpoint of snap.

Snap, g. cm.

6th Bend th Bend 1st Bend Good-paper cards- Poor-paper cards Plastic cards The above tests were made with cards 2%" x 3%" with the grain direction of the paper in the 3 direction. The cards were bent across the 2%" direction on testing for snap.

In addition to testing playing cards for snap, my machine can be used for testing other types of papers and pulps. For example, pulp is tested in the mill by beating in an experimental beater and making handsheets. The handsheets are then tested for Mullen, caliper, basis weight, etc. Typical pulps are listed in the following table and, in addition to the usual test values, the values for snap are shown.

B eating Time, min

Freeness, cc.

Pulp

1st 15th The need for a snap tester in the playing card field has been apparent for some time. I-Ieretofore playing cards have been tested for snap by snapping them with the fingernail while holding the other end in one hand. This test is quite arbitrary and gives no numerical value for snap. Cards with the best snap have been considered to be those that gave the loudest noise.

Snap or recovery is important in playing cards because of the constant bending and shuffling the cards receive in play. It has been shown that cards with good snap can be used longer than Y those with poor snap and still retain the property of straightening out when shufiled repeatedly.

It will also be apparent that other materials may be tested by my machines to record the fatigue of the same, under similar tests, as well as the elasticity thereof.

In accordance with the patent statues I have described the principles of operation of my Paper and material testing machine and have illustrated the best embodiment thereof; however, I desire to have it understood that variations and changes may be made within the scope of the following claims Without departing from the spirit of the invention.

I claim:

1. A material testing device comprising an electric motor, a transmission adapted to be driven by said motor, a shaft adapted to be driven by said motor, a shaft adapted to be driven at a constant speed from said transmission, an arm carried by said shaft, a flexing rod adjustably supported to said arm, an adjustable inclined table having a track formed therein, a steel ball adapted to roll in said track, a hammer pivoted in a manner to strike said ball, a clamp adapted to engage a sheet of material to be tested, a mandril adjacent said clamp over which the material is adapted to be bent, said flexing rod carried by said arm being adapted to bend the material held in said clamp and to release the same from bent position causing the material to strike said hammer and, in turn, to force said ball up said inclined track to indicate the flexing power of the material being tested by indicating along said track in degrees the height to which said ball travels thereon when struck by said hammer.

2. A material tester comprising a clamp for engaging one end of said material leaving the other end thereof free to flex, a mandril over which the material is adapted to be bent, means for bending the free end of the material over said mandril in a manner to release the free end of the material to permit it to snap back into normal position, an inclined track having a runway formed therein, gauge indicia formed along said runway, a ball adapted to be operated in said runway, pivoted hammer means at one end of said runway against which said ball normally rests whereby when the material snaps back from bending position, it will strike said hammer means and force said ball up said runway to indicate by said gauge indicia the snap recovery of the material being tested.

3. A material tester including a base member, an adjustable table supported above said base to permit the same to be inclined at a predetermined angle, a track formed in said adjustable table, a metal ball adapted to roll in said track, a hammer means adapted to drive said ball up said track, said ball normally resting against said hammer, means for supporting asheet of material to be tested with the free end thereof in a position to snap against said hammer means in the recovery of the material to normal position, and power and hand means for intermittently bending the material and causing the free end thereof to snap against said hammer means to drive said ball along said track to record the power of recovery of the material after it has been bent to indicate the fatigue of the material through a series of bends.

4. A device for testing the resiliency and fatigue of material including a mandril, releasable clamp means for retaining a piece of material terial over said mandril, pivoted hammer means adapted to be struck by the released free end of said piece of material, a ball adapted to be struck by said hammer means, an adjustable track for said ball, means for indicating the progress of said ball in said track when struck by said pivoted hammer and means for actuating said bending and releasingmeans.

5. A device for testing the resiliency and fatigue of material consisting of a mandril, re-

leasable clamp means for retaining a piece of material adjacent said mandril, means for bending and releasing the free end of a piece of material over said mandril, gauge means adjacent 8 6. A testing device as defined in claim 51 wherein the gauge comprises an arcuate scale and the indicator means comprises a pendulum carrying a pointer movable along said scale.

CHARLES E. JOHNSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,491,949 Francke Apr. 29, 1924 1,543,560 Eberhardt June 23, 1925 2,113,389 Smith Apr. 5, 1-938 2,281,163 Lane Apr. 28, 1942 FOREIGN PATENTS Number Country Date 185,253 Great Britain Sept. '7, 1922

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