US3689938A - Chronograph for an oscillograph - Google Patents

Abstract

The chronograph drum is mounted in fixed bearings at top and bottom so as to rotate in a fixed vertical axis. The drum can be driven at high or low speed by a motor.

Description

[4 Sept. 5, 1972 CHRONOGRAPH FOR AN [56] References Cited UNITED STATES PATENTS OSC ILLOGRAPH [72] Inventor: Felix L. Yerzley, Verona, NJ.

3,354,701' 11/1967 Yerzley......................346/7X [73] Assignee: Yerzley&Co., Newark, NJ.

[22] Filed:

Feb. 9, 1970 Attorney-Kenyon and Kenyon Related US. Application Data [62] Division of Ser. No. 751,293, Aug. 8, 1968,

[57] ABSTRACT The chronograph drum is mounted in fixed bearings at Pat. No. 3,518,876.

top and bottom so as to rotate in a fixed vertical axis.

The drum can be driven at high or low speed by a mo- I01.

521 US. 51 Im. 15/26 v [58] Field ofSearch. 58]l2 E, 125 0; 346/138,

4Clnims,3DrawingFigures PATENTEDSEP 1w 3.689 938 SHEU EN 3 CIIRONOGRAPH FOR AN OSCILLOGRAPH This is a division of application Ser. No. 751,293, filed Aug. 8, 1968, now US. Pat. No. 3,518,876.

' oscillographs have been known, for example, asin US. Pat. No. 3,354,701, wherein a beam which is mounted for pivoting about a fulcrum and initially locked in position receives a test specimen at one end and an unbalancing force at the other end. In addition, the beam cooperates with a fixed platen at the test specimen end against which the test specimen is initially positioned and a pen at the other end for recording the oscillations or amount of deflection of the beam on a chronograph chart'upon unlocking of the beam. In practice, such oscillographs may be utilized in accordance with test standards, ASTM D-945 for example.

Accordingly, it'is an object of the invention to maintain the recording drumof a chronograph in a vertical axis during rotation thereof in'a manner to eliminate an external support of the top bearing which is agreat handicap to the operator in installing and removing charts before and after tests.

Briefly, the invention provides an oscillograph having a very high degree of accuracy, for example, to 1 part in 5,000parts. The oscillograph includes abeam which is pivotally mounted by a depending knife edge and a mounting block having a V-shaped groove in which the bottom of the groove is mathematically defined by a projected joint so that the beam is pivotal on a substantially frictionless point-to-point fulcrum. Further, the beam cooperates with a recordingdrum which is rotatably mounted on a vertical axis and which is retained on the vertical axis during rotation so as to accurately record the beam oscillations. v

These and other objects of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1' illustrates a perspective view of an oscillograph according to the invention;

FIG. 2 illustrates a partial cross-sectional side view of the oscillograph of FIG. 1;

FIG. 3 illustrates a cross-sectional view of the chronograph of the invention taken on line 3-3 of FIG. 1; e

The oscillograph includes a support 21 of rectangular box-like configuration having a central opening 22 therein, a beam 23, pivotallyrnounted over the support 21 in line with the opening 22, a fixed platen assembly 24 over one section of the beam 23 and a chronograph 25 at the opposite end of the beam 23.

Referring to FIGS. 1 and 2, the beam 23 is formed as an I-beam so as to provide greater rigidity without increasing the moment of inertia and includes a yoke assembly 26 at a point near the center thereof which serves to pivotally mount the beam on a mounting block assembly 27 secured on the support 21. The yoke assembly 26 includes a pair of vertically upstanding bars 28 secured on the beam 23, as by welding, a horizontal plate 29 secured across the top surfaces of the bars 28, as by threaded bolts, and a knife edge assembly 30 which'is adjustably mounted on the underside of the plate 29, as by threaded bolts 31. The knife edge assembly 30 includes a bar 32 of hard steel or equivalent of triangular cross section having an optically straight and sharp depending apex which is rigidly secured within a mounting plate 33 of the knife edge assembly 30. The mounting block assembly 27 includes a pair of vertically disposed bars 35 which are removably secured on the support 21 as by threaded bolts 36 (FIG. 1), a horizontally disposed cross bar 37 extending across the top surfaces of the vertical bars 35 through the yoke assembly 26 of the beam 23, and a knife edge receiving assembly 38 secured to the cross bar 37. The knife edge receiving assembly 38 includes a block 39 of U-shaped cross section, a pair of inserts 40 within the block 39 forming a V-shaped' groove and a pair of bearing assemblies at the ends of the block 39. Each bearing assembly (FIG. 5) includes a stop plate 41 removably secured to the end of the block 39, a ball bearing 42 mounted within the stop plate 41, and a spring 43 which biases the ball bearing 42 toward the inserts 40 within the block 39. Each insert 40 is made of a hard material such as agate and is formed with a digitated edge facing the opposite insert (of FIG. 8). The inserts 40 are interengaged with each other and have downwardly inclined polished and optically flat upper surfaces which form the V-shapjed groove, the bottom of which mathematically defines a projected point. The bottom of the groove receives the apex of the knifeedge '32 of the yoke assembly 26 so as to pivotally support thebeam 23 in a point-to-point contact relationship. Reference is made to US. Pat. No 3,518,876 for further details of the oscillograph.

Referring to FIGS. 1 and 3, the chronograph 25 includes a drum 98 which is rotatably mounted on a pedestal 99 and driven through a suitable electric motor 100. The motor 100 is of known construction and is mounted within a housing 101 secured to the pen end of the support 21 by a pair of brackets 101'. The

' motor 100 further includes a high speed drive 102 and a low speed drive 103 which are connected via a suitable transmission 104 to a common drive shaft 105 for driving the drum 98 at either a high or a low speed rotation. In order to actuate the drives 102, '103, as indicated by a signal light 106 the motor 100 is provided with a pair of manual switches 107 for selective actuation of the desired drive. I Referring to FIG. 3, the pedestal 99 includes a vertically disposed shaft 108 which is clamped to the drive shaft 105 of the motor 100 for rotation therewith. The shaft 108 is journalled in the pedestal 99 by an anti-friction thrust bearing 110 at one end and by an anti-friction radial and thrust bearing 111 at the other end of the pedestal 99 and held against the bearings 110, 111 by suitable collars 112 fixed to the shaft 108 as shown. In addition, the pedestal 99 is fixed to the motor housing 101 by threaded bolts 113.

In order to mount the drum 98 on the pedestal 99, a teflon bearing ring 114 is secured within the lower end of the drum 98 and is slidably mounted about the pedestal 99. Also, a sleeve 115 is slidably mounted on the shaft 108. The upper end of the drum 98 is closed by the inserted disc 109 which rests rotably, except for friction due to the weight of drum 98 acting on the interface between disc 109 and sleeve 115, on the upper horizontal surface of sleeve 115. Concentricity of drum 98 and sleeve 115 is maintained by bushing 122 which is a press fit into bushing 1 15 but is dimensioned to provide rotational freedom for disc 109 which carries drum 98. The sleeve 115 further carries a key 116 95 with the shaft. The drum 98is thus supported at both ends by slidable bearings'coaxial with the shaft 108. Drum 98 thus normally rotates with shaft 108 but may be manually reset into a new rotational position by twisting disc 109 about the bushing 122 whether the shaft'108 is being driven or not. Manual setting of the drum position is. part of .static load-deflection test procedures.

' In order to raise the drum 98 vertically above the pedestal 99, a threaded axial screw 1 18 is threaded longitudinally into a complimentary bore l19.of the shaft 108 and a micrometer head 120 is fixedly secured as by a set screw 121 to the upper end of the threaded screw 118. In addition,-the bushing'122 is fixed within the top end of the drum 98 for threaded passage, of the threaded screw 118 therethrough. In operation, upon being turned in a first direction, the screw 118 raises up out of the shaft 108 and thereby carries the drum 98 via the bushing 122 therewith. Counter rotation of the threaded screw 118 causes movement into the bore 119 of the shaft 108 and consequent downward move I ment of the drum 98." With this arrangement, the only significant friction on the drum 98 is that of the record ing pen 89 and thus only a small frictional drive torque on the sleeve 115 via the key 116-is sufficient to drive the drum 98 by the frictional engagement from the top of sleeve 1 to the underside of disc 109.

It is noted that when the motor 100 is turned-off, it is 4 that the beam 23 will pivot under the influence of the weight 73 about the fulcrum of the beam 23 so as to compress the spring 66 against the abutment head 64.

The downward movement of the beam 23 is recorded the beam 23 i caused to i ot in a ou ter dir c ion and the upwar movementbf the pen89 i recorded on the chart 123. Continued oscillations of the beam 23 under the influence of the weights 73 and the spring 66 are thereafter recorded on the chart 123 in the known manner. After the beam 23. has oscillated until the oscillations are damped out or reach a minimal amount, the test is ended and the beam 23'is again locked in place by re-engagement of therelease assembly 83. The chart 123 is then removed from the drum 98 in order for various mathematical computations to be carried out to determine the resiliency and various other characteristics of the spring 66.

It is further noted that the invention-provides an oscillograph which has a very high degree of precision due in part to the various frictionless mountings of one movable member on another. Because of this precision,

possible to manually adjust the vertical position of the drum 98 independently of the rotation of the drum. Thatis, the d'rum98 can be turned manually through turning of the thumb screw 120. Otherwise, when the motor 100 is switched on to one of the drives 102, 103, the drum-98 is rotated in a constant horizontal plane about the axis of the shaft 108 by rotation of the shaft 108 through the drive shaft 105 of the transmission 104..

Referring to FIG. 1, in order to record the movements of the beam 23 during a test procedure, a chronograph chart 123 is mounted circumferentially on the drum 95 to receive the markings of the recording pen 89.

Referring to FIG. 1, the operation of the oscillograph is similar to that as described in ASTM standard test a method D-945-59. For example, in order to test for resiliency, the coil spring 66 is mounted on the mounting plate platform 60 and the beam 23 is then balanced in' order to apply an initial zero load. Thereafter, the beam 23 is locked in an elevated position by engagement of the release hook 83 of the release assembly 83 and the abutment head 64 of the platen assembly 24 is brought down against the spring 66 so as to hold it in a snug relationship. Next, a suitable number of standard weight placed on one of the shafts 72 in an unbalanced arrangement with respect to the beam axis. The member 83' is then pivoted to release the beam 23 so the oscillograph can be used to measure various static and dynamic characteristics not only of vulcanized products but also of products suchas steel, plastics, sponge material, andthe like. It is further noted that the oscillograph can record continuous oscillations of the beam 23automatically with the drum 98 being driven by means of the motor 100. Additionally, static tests can be run by rotating the drum 98 in increments either manually or through the motor 100.

WHAT IS CLAIMED IS: 7 1. A chronograph comprising a drive motor; a shaft connected to said motor for rotation thereby; a first bushing fixedly secured to said motor concentrically of said shaft; and a drum slidably mounted on said shaft for rotation therewith, said drum including a bearing fixed thereon at one end and slidably mounted on said first bushing, a second busing fixed on said drum at an end opposite said one end of said drum and slidably mounted on said shaft, and key means in said second bushing and said shaft for keying said second bushing to said shaft for rotation therewith. 2 A chronograph as set forth in claim 1 wherein said drum further includes a third bushing fixed within one

Claims (4)

1. A chronograph comprising a drive motor; a shaft connected to said motor for rotation thereby; a first bushing fixedly secured to said motor concentrically of said shaft; and a drum slidably mounted on said shaft for rotation therewith, said drum including a bearing fixed thereon at one end and slidably mounted on said first bushing, a second busing fixed on said drum at an end opposite said one end of said drum and slidably mounted on said shaft, and key means in said second bushing and said shaft for keying said second bushing to said shaft for rotation therewith.

2. A chronograph as set forth in claim 1 wherein said drum further includes a third bushing fixed within one end of said second bushing, and a threaded screw threadably mounted in said third bushing and threadably received in said shaft longitudinally thereof, whereby rotation of said threaded screw relative to said shaft causes longitudinal sliding of said drum relative to said shaft.

3. A chronograph as set forth in claim 1 wherein said bearing is an annular ring.

4. A chronograph as set forth in claim 1 wherein said bearing is an annular ring of Teflon.

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