US3777643A

US3777643A - Area source of collimated light and scanning mechanism

Info

Publication number: US3777643A
Application number: US00246979A
Authority: US
Inventors: C Asbelle; G Porter
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1972-04-24
Filing date: 1972-04-24
Publication date: 1973-12-11
Anticipated expiration: 1990-12-11

Abstract

A method using a light source scanning and tilting table combination device for producing a silhouette pattern of a patient''s extremities under weight bearing conditions. The collimated light source scanning mechanism for designing an orthopedic appliance comprises a tilting table with a transparent grid matrix and a movable area source of parallel collimated light. A silhouette of the area of interest is made by exposing the light sensitive paper located in the grid matrix with a beam of collimated light. The light source is arranged above the tilting table so that the subject may be positioned at a selected location from horizontal to vertical position.

Description

[ Dec. 11, 1973 AREA SOURCE OF COLLIMATED LIGHT AND SCANNING MECHANISM [75] Inventors: Charles C. Asbelle; Gerald K.

Porter, both of Oakland, Calif.

[73] Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.

221 Filed: Apr. 24,1972

21 Appl. No.: 246,979

[52] U.S. Cl 95/12, 177/209, 250/53,

355/67, 355/78, 355/84, 355/113, 346/107 R [51] Int. Cl. G0ld 9/42 [58] Field of Search 95/12; 250/50, 53;

2,095,268 10/1937 Roberts ..197/209X 3,688,676 9/1972 Cruickshank 346/107 R X 3,305,036 2/1967 Walters 177/209 3,171,959 3/1965 Kozek 250/53 Primary ExaminerSamuel S. Matthews Assistant Examiner-Michael D. Harris Att0rneyR. S. Sciascia et al.

[57] ABSTRACT A method using a light source scanning and tilting table combination device for producing a silhouette pattern of a patients extremities under weight bearing conditions. The collimated light source scanning mechanism for designing an orthopedic appliance comprises a tilting table with a transparent grid matrix and a movable area source of parallel collimated light. A silhouette of the area of interest is made by exposing the light sensitive paper located in the grid matrix with a beam of collimated light. The light source is arranged above the tilting table so that the subject may be positioned at a selected location from horizontal to vertical position.

10 Claims, 10 Drawing Figures SHEUZUFG PAIENIEI] DUI I I 5975 FIG 3 PAIENIEDBEEIHBB 3.777. 643

sum 3 N4 ELEVATION ELECTRICAL DRIVE DRIVE MECHANICAL DRIVE [Li HANDLE ELECTRIC -fl W MOTOR FRICTION CLUTCH F|G. 5

I AREA SOURCE OF COLLIMATED LIGHT AND SCANNING MECHANISM BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a device for designing orthopedic appliances and more particularly to a collimated light screening mechanism for designing an orthopedic appliance for the upper and lower extremities.

2. Description of the Prior Art In the construction of braces and limbs, individual patterns of patients are used to facilitate their fabrication and fitting.

For simplicity, the following pertains to tracings of the leg. Observations to be made, however, are considered equally applicable to other segments of the body, including upper extremity amputations and orthopaedic bracing of the head, neck, shoulders, torso and spine.

Conventionally, patterns are in the form of tracings made of the affected part. They are generally pencil outlines scribed onpaper to depict the contours involved. They thus represent two-dimensional patterns of a three-dimensional object. Additionally, notes are usually made on the pattern to indicate joint axes, bony landmarks and'other topography useful in making and fitting a properly conforming prosthesis. Commonly the tracing paper is ordinary brown wrapping paper.

Braces are prescribed to support, splint, immobilize or restrain, thereby returning and maintaining injured, broken, diseased or otherwise displaced bone to its natural position to promote healing.

Basically, the skeletal system represents the framework and the structural members of the body which are arranged and so articulated as to allow for mobility and locomotion. The skeletal apparatus also serves as a particularly efficient lever system. When combined with its associated system of muscles, providing force for motion and/or stabilization of the bony levers, purposeful and protective movement of the body is achieved.

In the present state of the art, braces and artificial limbs are basically crustacean-like in their manner of attachment and the way, they provide peripheral support. They thus perform their intended function of supporting the bony elements but only through the soft tissues. The point here is that the intervening soft tissues between the internal bone and weight-assuming elements of the external prosthesis represent a variable of substantial import. Bones give form to the body while soft tissues give shape and contour.

The usual tracing sometimes assumes singular characteristics reflecting not only the individuality of the patient and his orthopaedic problem, or problems, but also the individual technique of the person who made the tracing as well. The inventors critically examined certain fundamentals of the present tracing mode with a view toward stating the principal deficiencies for the purpose of attempting to correct same.

The bracemaker usually makes his own tracings. The value of reposing complete responsibility for proper production of the brace in the hands of one man is unquestioned. Obviously, situations are easily imagined where one bracemaker might well make a tracing from which a second bracemaker could fabricate the device. In view of the economics involved, this would seem to be desirable. The proposed technique seeks to establish and environment and language to promote widespread, meaningful and clearly understandable exchange of information between all bracemakers. Many bracemakers have their own favorite technique used in making their own tracings. The ability of one bracemaker to communicate with another bracemaker through the medium of his tracings leaves much to be desired because there is no standard method or common language necessarily agreed upon and used between the two artisans. I

Present tracing methods are inexact. Bracemakers are required to apply their own judgment when tracing a contour. Thisis commonly affected by the physical condition of the soft tissues, that is, whether firm or flaccid, edematous, etc. Consideration of these factors causes individual interpretations of such factors. At the knee, for instance, the center of rotation shifts according to the degree of flexion of that member and thus again requires judgment on the part of the tracer. Benefitting from study and experience, most fitters apply certain rules of thumb for fitting allowances which become important when different rules are employed.

Apparently, one example of a traditional source of error when the tracing is made lies in the position of the subject. The patient ordinarily lies on his back upon a flat, horizontal table. I-Iere gravity applies itself at right angles to the longitudinal axis of the leg. Frequently the soft tissues, especially when flacid, tend to flatten out against the supporting surfaces to distort the contours. In the supine position the musculature is relaxed and there is no significant compression of the articulations of the joints. As a consequence, while the leg will refleet one set of contours and joint axis measurements in that position, they may be considerably different when the patient is tilted into a vertical, or near-vertical plane, approaching the angle in which the planned brace will be used.

More specifically, the old method of manufacturing orthopedic appliances, such as braces, was to make a manual tracing of the patients limb or extremities of interest, with a pencil held vertically to a sheet of paper on which the patient was reclining. To accomplish reproducable results by this method a great deal of dexterity and skill was necessary, and it was found that a clear silhouette was difficult to obtain because the soft tissues of the patients limb of interest caused a distorted outline while in the supine position, the position required for an outline tracing of the limb.

SUMMARY OF THE INVENTION Briefly, the present invention is a collimated light scanning mechanism for designing an orthopedic appliance by reproducing an accurate pattern of the patients extremity of interest comprising a tilting table with a transparent grid matrix and a movable area source of parallel collimated light. The present invention further includes the unique method for performing the function. A silhouette of the area of interest is made by exposing the light sensitive paper located in the grid matrix with a beam of collimated light. The light is arranged on the tilting table so that the subject may be positioned at a selected location from horizontal to vertical position.

The present invention overcomes the aforementioned problems in that the patterns produced are more accurate and reproducable than those produced by the hand-held-pencil-tracing method. Moreover, the skill level is very low as compared to the former method. A silhouette of the area of interest is made, by the new method, by exposing light sensitive paper with a beam of collimated light. The collimated light, being parallel, produces a one-to-one silhouette irrespective of the distance from the recording surface to the occluding body. In addition, a light scanning source is arranged above the tilting table so that the subject may be positioned anywhere from horizontal to vertical. The more nearly vertical, the less distortion of soft tissue and resultant inaccuracies. For areas of larger interest, the light source may be scanned by a motor driven system. The collimated light is produced by a point source, a short arc xenon lamp bulb with a fresnel lens located so that the lamp is at the focal length distance from the lens. The lamp and lens in conjunction produce the collimated light. The lamp has a spectral output that closely matches the maximum response (spectral) of the light sensitive paper which is located beneath the grid matrix. The lens is of thin acrylic plastic which is transparent to the irradiance of interest and lightweight enough to be self supporting in the large required size. A glass lens would not be suitable for this application and a conventional lamp would not provide the required point source.

STATEMENTS OF THE OBJECTS OF THE INVENTION A primary object of the present invention is to provide a pattern of the body or extremity for the purpose of record and subsequent manufacturing of an orthopedic appliance.

Another object of the present invention is to produce an accurate pattern by a more automated method.

Another object of the present invention is to reduce the skill level required to mass produce anorthopedic appliance.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of the scanning device illustrating the drive track support mechanism, the solenoid and the electric mechanical drive and tilt table;

FIG. 2 is an isometric view of the opposite side of the scanning device illustrated in FIG. 1 and illustrating the ball bearing slide mechanism and the dual track mounts;

FIG. 3 is an isometric view of the scanning device of FIG, 1 in the elevated position and particularly illustrating the tilting mechanism;

FIG. 4A-is an isometric view of the top of the tilt table and scanning device illustrated in FIG. I and particularly illustrating the transparent grid position of the table;

FIG. 4B is an illustration of the transparent grid of FIG. 4A with a silhouette of the lower extremities superimposed over the grid matrix and as it would appear on exposed light sensitive paper;

FIG. 5 is a schematic drawing of the electric matrix tilt drivemechanism with a dual clutch device shown in FIG. 3;

FIG. 6A is an end view of the tilt table of FIG. 2 showing the spacer footrest and its attachment strips;

FIG. 6B is an end view of the tilt table of FIG. 1 illustrating the spacer footrest replaced with a weight distribution scale;

FIG. 7A is a transverse sectional view of the scanner parts being broken away to illustrate the interior construction, taken along line 7A-7A of FIG. 2;

FIG. 7B is a side sectional view of the scanner parts being broken away to illustrate the interior construction, taken along line 7B-7B of FIG. 7A.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1, 2 and 3, the scanning device 11 comprises the following major components: a modified tilt table 13, transparent grid matrix 13A, the grid lines being shown only in FIG. 4A for simplicity of illustration, spacer 15 or scales 15A (see FIG. 6B), motor drive mechanism 17, and an area source of collimated light device 21. The tilt table 13 can be a LaBerne Physical Therapy Table or the equivalent. Table 13 is modified to accept transparent grid matrix 13A and other pertinent equipment for the specific function desired, which will be described in detail later in the specification.

Referring to FIGS. 2, 6A and 6B, the spacer l5 acts as a footrest or can be replaced with scales 15A. The scales 15A are a pair of adjacently mounted scales such as the typical bathroom scales or the equivalent. Spacer l5 and scales 15A have two long extension strips 16A, 16B and 16E, 16F respectively which can be inserted into

slots

16C and 16D on the transparent grid matrix 13A at end of table 13. Scales 15A are used to divide the weight of the patient equally over the area between the patients legs in order to distribute equally the weight on both limbs.

Referring to FIGS. 3 and 5, the motor driven mechanism 17 is a standard electric motor with a dual clutch drive with a manual override handle 20 which engages the clutch for a manual drive, having a configuration as illustrated in FIG. 5. The motor driven mechanism 17 will drive elevation drive 19 to elevate or lower table 13 to the proper angle desired so that when the handle 20 is moved to engage friction clutch, the electrical drive will override the mechanical elevation drive shaft causing it to move upward to tilt table 13 to the vertical position. When handle 20 is operated to disengage the a friction clutch, table 13 may then be elevated to the vertical by cranking handle 22.

Referring to FIGS. 2, 7A and 7B, the area source of collimated light device 21 is slidably attached to

tracks

23A and 238 which are coupled to track mounts 23. The track mounts 23 are attached to the tilt table 13, as illustrated in FIG. 2, or with standard attaching devices. The collimated light source device 21 is located some distance above tilt table 13 and is further supported by drive track support mechanism 45. Ball bearing sliding mechanism 27 is slidably attached to

tracks

23A and 238 by attaching

brackets

18A, 18B, 18C, and 18D and can be powered by a drive motor 25. By replacing track 23A with a helical threaded drive screw mechanism 28 the collimated light device 21 may be made to automatically scan the rectangular area of grid matrix 13A. The helical threaded drive screw mechanism 28, which is operatively connected to drive motor 25, advances along the drive screw mechanism 28 and drives the collimated light device 21 in a plane parallel at the desired distance above table 13 and encompassing the area of grid matrix 13A. Motor 25, driving the helical threaded drive screw mechanism 28, may be a standard Dayton right angle gear motor or its equivalent.

The collimated light source device 21 includes a solenoid door activator 49 to activate door 52 which is attached to solenoid 49 through activator lever 51. The light enclosure package 53 includes a light source L and door 52. The light source or lamp L operates continuously so that when solenoid 49 activates door 52 the light impinges on reflecting mirror 57 which directs the reflected light rays on the fresnel lens 59 and onto the grid matrix 13A area to be scanned. The distance from lamp' L to mirror surface 57, or distance a, plus the distance from mirror surface 57 to the fresnel lens 59, or distance b, is equal to the focal length f of fresnel lens 59; that is, a b =f of fresnel lens 59. Lamp L is powered by power source 26 which maintains lamp L in continuous operation. Lamp L is at focal length f from fresnel lens 59 so that the light will be collimated to impinge on the grid matrix 13A area to be scanned. When light sensitive paper 47 is placed beneath the transparent grid matrix 13A, with the patient lying on the surface of table 13 and solenoid 49 is activated while motor 25 is operative, a silhouette of the patients extremities is reproduced onto the light sensitive paper 47. The drive mechanism 25 may operate in simultaneous sequence with the activation solenoid 51 so that a proper exposure is obtained during the scanning function. This function is neither necessary nor critical for the operation of the system. This sequential of operation may be accomplished by any appropriate means, either mechanical or electrical.

Referring to FIGS. 3, 7A and 7B, sensitive paper holding unit 29 comprises the following: retractable paper retaining plate 31, spring loaded cams 35 and cam rollers 37. The upper surface of plate 31 functions to retain paper 47 and the lower surface 39 functions as a cam follower. Cam activating handle 41 isspring activated bycam activator spring 43. When cam activating handle 41 is retracted, the tension on spring 43 causes rollers 37 to move horizontally thus rotating cams35 to the open position. Light sensitive paper 47, such as ozlid paper, or photograph paper or the like, may then be inserted. The handle 41 is then retracted to allow plate 31 to raise paper 47 against the undersurface of grid matrix 13A.

Referring to FIGS. 4A, 4B and 6B, transparent grid matrix 13A is etched or superimposed with a matrix scale, division lines from 0 to 40 inches and divided in half by a center line C so that when a patients body parts are silhouetted on the photo paper 47 a series of measurement lines are superimposed on the paper 47. This allows the brace maker to follow an exact pattern when bending and contouring the brace materials. The scales A are used to distribute the patients weight evenly when the tilt table 13 is in the near vertical position so that the patient can readjust his position to distribute his weight evenly along center line C. The exposed paper 47 can be developed by any standard method well known in the art. The tilt table 13 may be equipped with a protractor set to read at 90 in the hortional contours and the joint axes approach their natural weight bearing composition. This eliminates the problem of the bracemaker constantly refitting and adjusting the brace by hit or miss methods since he has an accurate pattern to follow.

Basically, the new method and device are considered to offer the following significant features. First, a simple and rapid process for making and substituting a silhouette for a tracing of the body part to be reproduced. Light sensitive paper, comparable to brown wrapping paper in cost, can be used to produce the silhouette in a matter of seconds. Secondly, when the silhouette is made, the position of the patient is changed from the conventional horizontal supine to a vertical or nearvertical position. The sometimes flaccid tissues involved are thus brought into the contour they will assume when the brace or limb is to be used. The joints involved are likewise brought into their compacted position. The resultant changes in contour and in joint position are considered to be significant.

The operation of the previously described apparatus is as follows:

a. Placing the patient on tilting table 13 with the patients extremities aligned over, above and adjacent transparent grid matrix 13A which is located in the planar surface of table 13;

b. Placing light sensitive paper 47 beneath the grid matrix 13A;

c. Tilting the tilting table 13 to about the vertical position; and

d. Scanning the areas of the grid matrix 13A with the scanning device 21 located above the grid matrix 13A and the patients extremities. The scanning device 21 scans along a direction back and forth in a plane parallel with the tilting table 13, simultaneously with the activation of the operative light source L, while the patient lies on table 13 in the vertical position, aligned with center line C of grid matrix 13A, while the patients body weight is adjusted so that scales 15A show an equal distribution of weight.

What is claimed is:

l. A method for obtaining a silhouette of a patients body parts comprising the steps of:

a. placing said patient next to a light sensitive surface;

b. exposing said patient and said light surface to a source of collimated light to reproduce a facsimile silhouette of a patients body parts on the side o'pposite said light sensitive surface and said patient;

c. continuously scanning along the body parts with said source of collimated light whereby said body parts precludes the light from said source from contacting said light sensitive surface and allowing the scanning light to impinge upon said light sensitive surface while exposing said light sensitive surface to provide a facsimile silhouette of said body parts.

2. The method recited in claim 1 wherein said collimated light continually scans along a transverse direction in a plane parallel with said light sensitive surface.

3. The method recited in claim 1 wherein said method further includes the step of intermittently activating a light means within said scanning light while simultaneously scanning along a planer direction and in a plane parallel with said light sensitive surface while elevating said light sensitive surface to a vertical position with respect to the normal horizontal of said light sensitive surface.

4. A device for obtaining a facsimile silhouette of a patients body parts comprising:

a. means for supporting said patient upon a substantially planer surface;

b. said means having a planer transparent member;

0. a light sensitive material;

d. a means for holding light sensitive material located contiguous to said transparent member;

e. a collimated light source;

f. a means for continuously scanning the collimated light source to expose said light sensitive material;

g. said device being designed so that said patient is located adjacent said means for supporting said patient and between said light source wherein said transparent member is between said patient and said means for holding light sensitive material.

5. The device recited in claim 4 wherein said means for supporting said patient further includes a tilting means to tilt said supporting means to a vertical position with respect to the normal horizontal of said means for supporting said patient.

6. The device recited in claim 5 further including a weight distribution means so that when said supporting means is in the vertical position said weight distribution means will indicate the weight distribution on each of the patients limbs.

7. The device recited in claim 4 wherein said transparent member further includes a grid with grid lines superimposed onto said transparent member.

8. The device recited in claim 4 wherein said light sensitive material is located and encompasses the area mating lens.

Claims

1. A method for obtaining a silhouette of a patient''s body parts comprising the steps of: a. placing said patient next to a light sensitive surface; b. exposing said patient and said light surface to a source of collimated light to reproduce a facsimile silhouette of a patient''s body parts on the side opposite said light sensitive surface and said patient; c. continuously scanning along the body parts with said source of collimated light whereby said body parts precludes the light from said source from contacting said light sensitive surface and allowing the scanning light to impinge upon said light sensitive surface while exposing said light sensitive surface to provide a facsimile silhouette of said body parts.

4. A device for obtaining a facsimile silhouette of a patient''s body parts comprising: a. means for supporting said patient upon a substantially planer surface; b. said means having a planer transparent member; c. a light sensitive material; d. a means for holding light sensitive material located contiguous to said transparent member; e. a collimated light source; f. a means for continuously scanning the collimated light source to expose said light sensitive material; g. said device being designed so that said patient is located adjacent said means for supporting said patient and between said light source wherein said transparent member is between said patient and said means for holding light sensitive material.

6. The device recited in claim 5 further including a weight distribution means so that when said supporting means is in the vertical position said weight distribution means will indicate the weight distribution on each of the patient''s limbs.

8. The device recited in claim 4 wherein said light sensitive material is located and encompasses the area beneath said transparent member.

9. The device recited in claim 4 wherein said light source scanning means is an intermittently operative collimated light source located directly above said transparent member and scans in a plane parallel with said support means wherein said light source exposes said light sensitive material.

10. The device recited in claim 9 wherein said collimated light source comprises an intermittently operative light means located directly above said transparent member and at the focal length distance above a collimating lens.