US2026907A - Radiographic plate changer - Google Patents

Description

M. MORRISON RADIOGRAPHI C PLATE CHANGER Y Jan. 7, 1936.

Filed April 4, 1931 INVENTOR ATTORNEY Patented Jan. 7, 1936 UNITED STATES PATENT FFICE RBIOGRAPHC PLATE CHANGER ration of Delaware Appiication April 4, i931, Serial No. 527,659

11 Claims.

My invention relates to plate' changers for radiographic apparatus and are sometimes referred to in the art as serialographs. Devices of this general character are well known in the art for exposing a plurality of sensitized films to X- radiation emanating from an X-ray tube and a device of this character is usually employed in taking stereoscopic radiographic pictures of an object in which the angle between the X-ray tube and the plate changer is changed with the exposure of each film. This latter is usually accomplished by changing the angle of the plate changer or the angle of the X-ray tube relative to the object to be radiographed.

Heretofore the operation of the plate changers have been dependent upon gravity, electric motor or fluid actuated mechanism. These devices are readily susceptible to Wear and break down and on the whole are unreliable and cumbersome.

It is, therefore, an object of my invention to provide a plate changer which is entirely automatically actuated by a mechanical device which is not readily susceptible to wear or break down.

Another object of my invention is to provide a plate changer in which each of the individual films assumes a position adjacent a portion of the apparatus which is pervious to X-rays for exposure of each lm,

Still further objects of my invention will become apparent to those skilled in the art by reference to the accompanying drawing wherein Fig. 1 is a rear plan view of my device; and

Fig. 2 is a sectional View taken on line lI-II of Fig. 1 with a portion of the apparatus broken away to better illustrate the mechanism.

Referring now to the drawing in detail I have shown a frame member 2 which is provided with a pair of. laterally extending lugs 3 and 4 at each end of the frame member. A pair of square tracks and 6 forming a guideway extend longitudinally of the frame member and are secured to these lateral lugs 3 3 and @-4 respectively. The track member 5 is hollow for a purpose more fully hereinafter explained.

A cassette tray i, provided with a pair of large rollers 8 and a plurality of pairs of smaller laterally disposed rollers S, is arranged to move longitudinally of the frame member by the rollers being in engagement with the pair of tracks 5 and S respectively. The cassette tray l is provided with a pair of. laterally extending lugs II and a coil spring I2 is secured to one of these lugs and to a bracket member I3. A similar coil spring i4 is secured to the other lug II and to a similar bracket member I5 disposed at the opposite end of the frame member 2.

A square shaft I6 is disposed internally of the hollow track 5 and is arranged to be moved longitudinally of this track member by means of a 5 control handle I'I to be more fully hereinafter described. The bracket members I3 and I5 are secured to the square shaft I6 and the coil springs l2 and I4 are likewise secured to these bracket members as before stated. The coil springs are, 10 however, secured to these bracket members by means of a set screw and lock nut arrangement in a well known manner for increasing or decreasing the tension of these coil springs.

The handle for control lever II is pivotally secured to a bracket member IB which is in turn rigidly secured to one of the surfaces of the track member 5.

A pin I9 is rigidly secured to the square shaft I B and extends through an elongated slot pro- 20 vided in the track member 5 and is pivotally secured to the handle of control lever I'I. The control lever I'I is provided with a pair of pivoted auxiliary handles 22 which engage a pair of pins 23 slidably mounted in bearings 23 and these 25 handles 22 are biased away from the lever I'I by means of a pair of coil springs 24. The bracket member I8 is provided with notches 25 which are engaged by the respective pins 23 as the control lever is rotated about its pivot.

The cassette tray 'I is provided on its rear surface with a pair of beveled stop plates 26, and a solenoid 2l having a spring pressed plunger 28 is arranged to engage the plates 26, and thus forms a detent to maintain the cassette tray at the respective limits of its travel, with the sensitized films carried by the cassette tray in alignment with a section of the frame member pervious to X-rays.

The frame member is provided with a cover 29 40 which supports a bracket 30 to which the solenoid 2l is secured and a similar cover 32 is secured to the front of the frame member and is provided with a section thereof pervious to X- rays and the remainder thereof opaque to X- rays. The sections of this cover opaque to X- rays are provided with suitable hinged doors 3l and 3 I for loading and unloading the films from the cassette tray.

The cassette tray is provided with a pair of pins 33 and 33 which are positioned to engage a pair of contact members 34 and 35 respectively, disposed at each end of the frame member 2.

A manually operable switch 35 is provided, which in actual practice, is usually mounted upon the control lever I1. This switch 36 is provided with a contact segment positioned to engage a plurality of contact terminals 31, 38 and 39 respectively. A conductor 40 extends from one of the contact members 35 to the contact terminal 31 and a similar conductor 42 extends from the contact member 34 to the contact terminal 39. A conductor 43 extends from the contact terminal 38 to a push button switch 44 and from this latter switch to a suitable attachment plug 45. A conductor 46 extends from the attachment plug 45 to the solenoid 21 while a conductor 41 interconnects the remaining contact members 34 and 35.

The operation of my device may be best understood by assuming a given operation. Assuming, therefore, it is desired to expose a series of sensitized films to the X-rays radiating from an X-ray tube the cassette tray 1 is initially moved to one of its extremities of travel longitudinally of the frame member 2, such as for example, to the position shown in dotted lines to the right of Fig. 1. One of the sections of the cover 32, which is provided with a door, is open and a sensitized film placed in the cassette tray.

The attachment plug 45 is connected to a suitable source of electrical energy and the switch 36 is moved to the position shown by the arrow establishing contact between the contact terminais 31 and 38. The contact terminals 35 are closed by the pin 33' when the cassette tray is in this position.

The push button switch 44 is then pressed to energize the solenoid 21 thus causing retraction of the spring pressed plunger 28 which disengages one of the stop plates 26 and allows the spring I4 which will be expanded with the cassette tray in the assumed position, to move the same longitudinally of the frame member to the left as shown in full lines in the figure. That section of the plate 32, which is also provided with a door opaque to X-rays, is then opened and a film inserted in this section of the cassette tray. The cassette tray being loaded with unexposed Illms is now ready for the taking of a radiographic picture. With the cassette tray in the position last mentioned, namely, to the left as shown in full lines in Fig. 1, the right hand section of the cassette tray 1 will be in alignment with the section of the cover 32, of the frame member 2, which is pervious to X-rays with the left hand section of the cassette tray disposed in back of one of the sections opaque to X-rays. l

The pin 33 of the cassette tray 1 will be in engagement with one of the pairs of the contact members 34 which will cause the closing of these contact members. The switch 36 is moved in the direction as shown in Fig. 1 which establishes connection between the contact terminals 38 and 39 and the contact members 35 will now be open. With the cassette tray in the position shown, namely to the left as shown in full lines in the figure, the coil spring I2 will be expanded and the coil spring I4 will be contracted.

As these two coil springs are of substantially the same tensile strength upon release of the cassette tray and its movement in response to the potential energy of the coil spring I2 a condition would occur where the potential energy of the respective springs I2 and I4 would tend to equalize each other, which condition would occur before the cassette tray 1 has moved sufficiently to the right, as shown in dotted lines in Figure l,

for one of the plates 26 to be engaged by the plunger 28 of the solenoid 21.

In order to increase the potential energy of the expanded spring I provide the control lever I1. This lever is provided with a pin I9 engaging the square shaft I6 and upon movement of the lever the square shaft I6 is moved internally of the track member 5. The bracket members I3 and I5 being secured to the respective springs I2 and I4 and to each end of the square shaft I6 causes further expansion of the coil spring I2 as the square shaft I6 is moved to the right, This further expansion of the coil spring increases the potential energy of the spring to an amount sufficient to overcome the potential energy of the spring I4 as the same tends to become effective during movement of the cassette tray, and allows the latter to move the additional required amount to permit the plunger of the solenoid to engage the stop plate 26 and maintain the cassette tray in its other extremity of travel.

Upon closing of the switch 44 the circuit will be completed to the solenoid 21, which extends from one side of the plug 45 through conductor 46, solenoid 21, conductor 41 through the contact members 34, conductor 42 to the contact terminal 39, through the switch 36 to the terminal 38, thence by means of conductor 43 through the switch 44 back to the other side of the plug 45, This allows the solenoid 21 to retract the plunger 28 and disengage the stop plate 26.

The coil spring I2 will then cause movement of the cassette tray 1 to the right, which due to the increased potential energy given the spring I2 by the control handle I1 will enable the spring pressed plunger 28 to engage the other plate 26 and maintain the cassette tray in a position shown in dotted lines.

As the cassette tray moves to this position the pin 33' will immediately cause the closing of the contact members 35, which would immediately cause the solenoid to become energized, should the operator still have the switch 44 closed,.were it not for the fact that the switch 36 has the circuit to the solenoid open, as well as the fact, that the pin 33 has opened the contact members 34 in moving to the right.

When it is desired to again have the cassette tray move to the left as shown in full lines, the switch 36 must be moved to the position shown by the arrow to establish a contact between the terminals 31 and 38 to partially complete the circuit to the solenoid. The control lever I1 must likewise be moved to the position as shown, as indicated by the arrow to move the square shaft I6 to the left and increase the potential energy of the spring I4 which would now be expanded. Immediately upon closure of the circuit by the operator actuating the switch 44 the cassette tray will be again released by the solenoid 21 and it will move from the position indicated in dotted lines to that shown in full lines.

It can thus be seen that once the cassette tray is moved to either of its positions and either of the respective springs I2 and I4 initially tensioned the operation of the device is entirely automatic.

Upon movement of the tray to one position, one of the springs becomes tensioned, while the other is contracted and upon movement of the cassette tray to the opposite position the inverse condition of the springs results. This enables each of the springs to alternately act as shock absorbers for the cassette tray while at the same time permitting the potential energy of the tensioned spring to move the tray to its limits of travel.

It is, therefore, obvious that the mechanism utilized for actuating the device is susceptible to very little Wear, is simple in construction and positive in its operation.

Although I have shown one specic embodiment of my invention I do not desire to be limited thereto as various other modications of the same may be made Without departing from the spirit and scope of the appended claims.

What is claimed is:

1. In an automatic plate changer for X-ray photography the combination of a guideway, a cassette tray movable longitudinally along said guideway, tensioning means connected at one end with said cassette tray, a vportion of said tensioning means serving to move the tray in one direction and the remaining portion thereof serving to move the tray in an opposite direction, means connected with the other end of said tensioning means for increasing the tension of either of said portions thereof, and releasable means cooperating with said cassette tray for holding the same stationary at predetermined points in its path of movement.

2. In an automatic plate changer for X-ray photography the combination of a frame member provided with a guideway, a cassette tray carried by said frame member and movable substantially the entire length thereof along said guideway, tensioning means connected to said cassette tray and operable to cause movement of the latter along said guideway in one direction, tensioning means connected to said cassette tray and operable to cause movement of the latter along said guideway in an opposite direction, said tensioning means being connected to said cassette tray in opposition with respect to each other, means connected with both of said tensioning means ,and operable to increase the potential energy of either of said tensioning means suiciently to cause said tensioning means having increased potential energy to cause movement of said cassette tray substantially the entire length of said frame member against the potential energy of said opposed tensioning means as the latter becomes effective during movement vof said cassette tray longitudinally of said frame member, and releasable means carried by said frame member and engageable with said cassette tray to maintain the latter at its extremities of travel against the potential energy of either of said tensioning means.

3. In an automatic plate changer for X-ray photography the combination of a frame member provided with a guideway, a cassette tray carried by said frame member and movable substantially the entire length thereof along said guideway, tensioning means connected to said cassette tray and operable to cause movement of the latter along said guideway in one direction, tensioning means connected to said cassette tray and operable to cause movement of the latter along said guideway in an opposite direction, said tensioning means being connected to said cassette tray in opposition with respect to each other, a detent carried by said frame member and engageable with said cassette tray for maintaining the latter at either oi its extremities of travel, means connected with both of said tensioning means and operable to increase the potential energy or" either of said tensioning means suiciently to cause said tensioning means having increased potential energy to move said cassette tray to an engaging position with said detent against the potential energy of said opposed tensioning means as the latter becomes effective during movement of said cassette tray longitudinally of said frame, and means carried by said frame member and responsive to actuation by an operator for releasing said detent and causing said tensioning means having increased potential energy to move said cassette tray.

4. In an automatic plate changer for X-ray photography the combination of a frame member provided with a portion pervious to X-rays and the remainder thereof opaque to X-rays, a guideway in said frame member and extending longitudinally thereof, a cassette tray for encasing a plurality of sensitized films disposed in said frame member and arranged to be automatically moved along said guideway longitudinally of said frame member, spring tensioning means connected to said cassette tray and operable to cause movement of the latter Within said frame along said guideway in one direction of travel, spring tensioning means connected to said cassette tray and operable to cause movement of the latter within said frame along said guideway in an opposite direction of travel, a detent carried by said frame member and engageable with said cassette tray to maintain the latter in various positions during its movement to cause at least one of said iilms to be always in a position relative to the portion of said frame member pervious to X-rays, manually operable means connected to both of said spring tensioning means and operable to increase the tension of either of said spring tensioning means, and electrically operated means carried by said frame member and operable to release said detent and render said spring tensioning means having increased tension eiective to move said cassette tray longitudinally of said frame member along said guideway.

5. In an automatic plate changer for X-ray photography the combination of a frame member provided with a guideway, a cover for said frame member provided with a portion pervious to X- rays and the remainder thereof opaque to X-rays, a cassette tray for encasing a plurality of sensitized lms disposed in said frame member and movable longitudinally thereof along said guide- Way, a pair of coil springs of substantially equal potential energy connected to said cassette tray, one of said coil springs being effective to cause movement of said cassette tray in one direction and the other of said springs being effective to cause movement of said cassette tray in the other direction, a detent carried by said frame member and engageable with said cassette tray to maintain the latter at either of its extremities of travel against the tension of one or the other or" said springs, manually operable means connected to both of said coil springs to increase the potential energy of the spring under tension when said cassette tray is at one extremity of travel, and electrically operated means carried by said frame member to cause said detent to disengage said cassette tray and cause thespring under tension to move said cassette tray longitudinally of said frame member along said guideway.

6. In an automatic plate changer for X-ray photography the combination of a frame member provided With a guideway, ,a cassette tray carried by said frame member and movable longitudinally thereof substantialy the entire length of said guideway, a coil spring connected to said cassette tray and operable to move the latter in one direction along said guideway, a coil spring connected to said cassette tray and operable to move the latter along said guideway in an opposite direction, mechanism connected to both of said coil springs. provided with an actuating leverand operable to increase the potential energy of each of said coil springs as the respective springs are tensioned by movement of said cassette tray, a solenoid carried by saidi frame member and provided with a plunger engageable with said cassette tray to maintain the latter in a xed position relative to said frame member, and manually operable means electrically connected to said solenoid to cause disengagement of the plunger relative to said cassette tray to render the respective spring under tension effective to move said cassette tray along said guideway longitudinally of said frame member.

'7. In an automatic plate changer for X-ray photography the combination of a frame member provided with a guideway, a cassette tray carried by said frame member and movable 1ongitudinally of the latter substantially the entire length of said guideway, a coil spring connected to said cassette tray and operable to move the latter in one direction along said guideway, a coil spring connected to said cassette tray and operable to move the latter along said guideway in an opposite direction, said coil springs being secured atone of their respective ends to said cassette tray and opposed relative to each other, mechanism connected to both of said coil springs provided with a manually operable lever and operable to increase the potential energy of each of said springs after the respective spring has been tensioned by movement of said cassette tray to cause said tensioned spring to move said cassette tray in an opposite direction against the potential energy of said opposed coil spring, and a detent carried by said frame member and engageable with said cassette tray and operable by a solenoid associated therewith to release said cassette tray and cause said tensioned coil'spring to move said cassette tray and tension the opposed coil spring preparatory to further movement of said cassette tray in a direction opposite to said rst mentioned direction.

8. In an automatic plate changer for X-ray photography the combination of a frame member provided with a guideway, a cassette tray carried by said frame member and movable longitudinally thereof along said guideway, tensioning means connected to said cassette tray and operable to cause movement thereof, a detent carried by said frame member and engageable with said cassette tray to maintain the latter at opposite limits of its longitudinal movement, electrically operated means associated with said detent for causing the release of the latter relative to said cassette tray, an electrical circuit including said electrically operated means, a switch, and a pair of contact members Adisposed at one end of said frame member, said contact members being actuable by movement of said cassette tray to open and close this circuit, a second electrical circuit including said electrically operated means, said switch, and a pair of contact members disposed at the opposite end of said frame member, said last mentioned contact members being actuable by movement of said cassette tray` for opening and closing this second circuit, and an auxiliary switch common to both of said circuits and operable to interrupt one of said circuits at a time to prevent the movement of said cassette tray from completing the circuit to said electrically operated means by closure of the contact members included in the circuit interrupted by said auxiliary switch, and again releasing Ysaid detent after said cassette tray has moved to one of its limits of travel, except by l5 operation of said iirst mentioned switch.

9. In an automatic plate changer for X-ray photography the combination of a frame member provided with a guideway, a cassette tray carried by said frame member and movable longitudinally of the latter substantially the entire length of said guideway, tensioning means connected to said cassette tray and operable to move the latter in one direction along said guideway, tensioning means connected to said cassette tray and operable to move the latter along said guideway in an opposite direction, said tensioning means being connected to said cassette tray in opposition relative to each other, a detent carried by said frame member and engageable with said cassette tray to maintain the latter at opposite limits of its longitudinal movement, means connected with both of said tensioning means and operable to increase the potential energy of either of said tensioning means sufficiently to cause said tensioning means having increased potential energy to move said cassette tray to an engaging position with said detent against the potential energy of said opposed tensioning means as the latter becomes effective during movement of said cassette tray, electrically operated means carried by said frame member for releasing the engagement of said detent relativel to said cassette tray, an electrical circuit including said electrically operated means, a switch, and a pair of contact members disposed at one end of said frame member, said contact members being actuable by movement of said cassette tray for opening and closing this circuit, a second electrical circuit including said electrically operated means, said switch, and a pair of contact members disposed at the other end of said frame member and actuable by movement of said cassette tray for opening and closing this second circuit, and an auxiliary switch common to both of said circuits and operable to interrupt one o1' said circuits at a time to prevent movement of said cassette tray from completing the circuit to said electrically operated means, by closure of the contact members included in the circuit interrupted by said auxiliary switch, and again releasing said detent after said cassette tray has moved to one of its limits of travel, except by operation of said first mentioned switch.

10. In an automatic plate changer for X-ray photography the combination of a frame member provided with a guideway, a cassette tray carried by said frame member and movable longitudinally of the latter substantially the entire length of said guideway, tensioning means connected to said cassette tray and operable to move the latter in one direction along said guideway, tensioning means connected to said cassette tray and operable to move the latter along said guideway in an opposite direction, mechanism connected to both of said tensioning means provided with a manually operable lever and operable to increase the tension of either of said tensioning means, electrically operated means carried by said frame member, and means engageable with said cassette tray and operable by said electrically operated means to render one of said tensioning means effective to move said cassette tray along said guideway longitudinally of said frame member.

il. n an automatic plate changer for X-ray photography the combination of a frame member provided with a guideway, a cassette tray carried by said frame member and movable longitudinally thereof along said guideway, a tensioning member connected toy said cassette tray for moving the latter along the guideway of said frame member in one direction, a tensioning member connected to said cassette tray for moving the latter along the guideway of said frame member in an opposite direction, means connected with both of said tensioning members and operable to increase the tension of one of said tensioning members at a time, electrically operated means carried by said frame member, and means engageable with said cassette tray for holding the latter at its extremities of travel against the tension of either of said tensioning members and operable by said electrically operated means in response to actuation by an operator to release said cassette tray thus causing said tensioning member having increased tension 10 to become eective and move said cassette tray.

MONTFORD MORRISON.

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