US2908742A - Captivated tube shield - Google Patents

Description

Oct. 13, 1959 H. J. MURPHY 2,908,742 CAPTIVATED TUBE SHIELD Filed July 13, 1956 IN VENTOR ATTORNEY the chassis.

United States Patent O CAPTIVATED TUBE SHIELD Howard J. Murphy, North Wilmington, Mass., assignor to United-Carr Fastener Corporation, Boston, Mass., a corporation of Delaware Application July 13, 1956, Serial No. 597,719

3 Claims. (Cl. 174-35) The present invention relates to an improved electrical shield construction, and more particularly to an improved tube shield construction for association with electron discharge tubes or the like in electrical apparatus to avoid undesirable reactions between the various ele ments thereof.

A wide variety of shielding means, generally identified as tube shields, have been employed heretofore in electrical apparatus, such as, for example, radio sets, to dissipate electro-magnetic and electrostatic fields set up therein by the electron discharge tubes during the operation of the apparatus. While such prior tube shields adequately perform their intended shielding function, such tube shields have possessed many disadvantages which have been found objectionable.

One of the most common forms of tube shields heretofore employed has consisted of a simple can or cylinder which is secured to the chassis in detachable relationship therewith by a friction fit or similar fastening means. When a tube is to be replaced in an apparatus employing the so-called can type tube shield, the tube shield is completely detached from the chassis of the apparatus, after which the tube is then replaced. Oftentimes the repairman or technician performing the operation will fail to replace the tube shield with a corresponding impairment in the operation of the apparatus. Moreover, the failure to replace the tube shield invariably results in the tube shield being left on the chassis, thereby resulting in the likelihood of a short circuiting of the electrical apparatus. Another disadvantage with the can type tube shield is that the continued insertion and withdrawal of the tube shield from time to time during the replacement results in a loose connection between the tube shield and the chassis. This Will result in a vibration of the tube shield, oftentimes not insuring a positive grounding of the shield to the chassis.

Another detachable form of tube shield that has received widespread usage is the so-called shaped shield. This type consists of two symmetrically paired parts of sheet metal and shaped to fit closely to the bulb of the tube. The paired parts are held together by a detachable ring, a detachable collar, or various other forms of clamping and connecting parts. Such shaped tube shields, in addition to the basic disadvantages attendant to detachable tube shields in general, suffer further in that all tubes are not one size. Therefore, several different sizes must be made and stocked, resulting in an unnecessary inventory. Moreover, the design and multiplicity of parts of the shaped tube shields have resulted in a relatively high cost for such shields, and they are awkward to assemble and difiicult to satisfactorily ground to the chassis.

Some attempts have been made to eliminate these disadvantages attendant to the various forms of detachable tube shields by fixedly securing the tube shields to Such fixed tube shield constructions have consisted of two mating or paired parts, each of which are hingedly connected at their bottom ends to one another or to the chassis. To replace a tube in an electrical apparatus employing such a construction, each of the mating parts is pivoted upwardly away from one another, the tube then replaced, and the component parts then pivoted inwardly to one another to envelop and shield the new tube. A principal disadvantage with this type of tube shield is that it is extravagant of chassis space and does not permit the positioning of the tubes to the manufacturers requirements. Another disadvantage with this form of shield is that latching or connecting means between the mating parts to insure proper engagement of the shield parts must be present, thereby increasing the complexity and cost of such tube shields. Therefore, the permanently afiixed tube shields heretofore developed have met with very little success since compactness of design and simplicity of construction are necessities in most electrical apparatus.

.11; is therefore a principal object in the elimination of the foregoing and related disadvantages to provide a new and novel tube shield construction overcoming the disadvantages inherent in previously employed tube shields.

Another object of the present invention is the provision of an improved tube shield construction which will permit replacement of a tube more easily than with prior tube shields.

Yet another object of the present invention is the provision of an improved tube shield construction which will be permanently afiixed to the chassis, thereby insuring the proper functioning of the tube shield at all times.

A further object of the present invention is the provision of an improved tube shield construction that requires a minimum amount of chassis space.

A still further object of the present invention is the provision of an improved tube shield construction in which the component parts will be in proper engagement with one another at all times.

Another object of the present invention is the provision of an improved tube shield construction that will remain in tight engagement and in proper grounded relationship with the chassis at all times.

A still further object of the present invention is the provision of an improved tube shield construction that is of extreme simplicity in design and operation, and inexpensive to manufacture.

Other and additional objects will become apparent from the ensuing description taken in conjunction with the accompanying drawings.

Broadly stated, in the attainment of the foregoing objects, the tube shield construction of the present invention comprises inner and outer sleeve means, one of said sleeve means having connecting means positioned at one end thereof for securing same to a chassis in fixed relationship thereto, the other of said sleeve means being rotatable relative to the fixed sleeve means, the top portion of the outer and inner sleeve means each being provided with diametrically opposed longitudinal slots therein, and stop means preferably being provided to limit the rotation of said rotatable sleeve means. The rotatable sleeve means is advantageously arranged exteriorly of the fixed sleeve means, and the assembly is preferably arranged to retain the rotatable sleeve means against removal.

To the accomplishment of the foregoing and related ends, the present invention then consists of the means hereinafter fully described and particularly pointed out in the claims, the annexed drawing and the following description setting forth in detail certain means in the carrying out of the invention, such disclosed means illustrating, however, but one of various Ways in which the principle of the invention may be employed.

The present invention is illustrated by' way of example in the accompanying drawings, in which:

Figure 1 is a perspective view of outer sleeve means forming a component part of a tube shield construction made in accordance with the present invention.

Figure 2'is a' perspective view of the inner sleeve means to be associated with said outer sleeve means to form a tube shield construction made in accordance with the present invention.

Figure 3 is a perspective view of a tube shield construction made in accordance with the present invention with the outer shield in opened position to permit the insertion or withdrawal of a tube.

Figure 4 is a perspective view of a tube shield construction made in accordance with the present invention illustrating the outer sleeve means in closed position to provide the desired shielding.

Reference is now to be had to the drawings wherein an illustrative embodiment of a tube shield construction made in accordance with the present invention and gen erally designated by reference numeral is shown. The tube shield construction 10 as shown comprises an outer tubular sleeve member A enveloping an inner tubular sleeve member B, one of which is to be fixedly secured to a support to permit relative rotation of the sleeve members A and B with respect to one another.

The outer tubular sleeve member A, as shown in Fig. 1, is of a height and diameter sufficient to envelop the desired electron discharge tube, and comprises a lower body portion 11 and a pair of opposed arm portions 12 and 13 extending upwardly therefrom in longitudinal alignment therewith. The opposed arm portions 12 and '13 result in the formation of opposed slots extending upwardly from the top free edges 14 and 15 of the lower body portion 11 and being of a width and longitudinal length suflicient to permit the engagement of the thumb and finger of a technician therebetween. Each of the arm portions 12 and 13 are provided with outwardly extending flange portions 16 and 17 extending longitudinally along each vertical side edge thereof to enable the sleeve member A to be rotated, and also to limit such rotation in a manner to be more fully described hereinafter.

The outer sleeve member A may be made from any suitable metal that is capable of possessing some degree of flexibility but yet has sufficient strength to resist bending or distortion. The outer sleeve member A may be made in any desired manner, and preferably is formed from a flat blank of sheet metal which is rolled to the required diameter with the free ends of the lower base portion 11 overlapping one another circumferentially as along the line 18.

The inner tubular sleeve member B, as shown in Fig. 2, likewise is of a height and diameter sufficient to envelop the electron discharge tube, although the diameter of the inner sleeve member B should be just slightly less than that of the outer sleeve member A, so as to permit the outer sleeve member A to be in engagement therewith and yet be readily rotatable therearound without creating unnecessary distortional strains.

The inner sleeve member B comprises a lower base portion 19 having a pair of opposed arm portions 20 and 21 extending upwardly therefrom in longitudinal alignment therewith. The length and the width of the arm portions 20 and 21 of the inner sleeve member B are substantially identical with the length and width of the arm portions 12 and 13 of the outer sleeve member A. Stop means in the form of a triangular ear portion 22 extends outwardly from the side edge of the arm portion 20 immediately adjacent the point of jointure with the lower base portion 19. The function of the ear portion 22 is to insure the positive retention of the outer sleeve member A on the inner sleeve member B, and to also limit the rotational movement of the outer sleeve by member A engaging the flange portions carried by the arms struction can be employed equally as well.

12 and 13 in a manner to be more fully described hereinafter.

The inner sleeve member B is provided with lug portions 23 at the bottom free end of the lower base portion 19 on opposite sides thereof to permit the engagement and securing of the inner sleeve member B to a chassis plate C by means of screws or bolts 24. It is to be clearly understood that these securing means are illustrative in character only, since there are a wide variety of other available attaching means by which the inner sleeve member B may be secured to the chassis C.

The inner sleeve member B may be made from the same material and in the same manner as the outer sleeve member A. A preferred method, as hereinbefore indicated, is to roll the sleeve member B from a flat blank to the desired diameter, with the free end of the lower base portion 19 overlapping one another along line 25.

To employ the tube shield construction 10, the inner sleeve member B is secured to the chassis C over the tube socket opening by means of the screw or bolt 25' passing through the lugs 24. To insert the outer sleeve member A over'the inner sleeve member B, the lower base portion 11 of the outer sleeve member A is placed over the free ends of the opposed arm portions 20 and 21 of the inner sleeve member B, and in longitudinal alignment therewith. The outer sleeve member A is then slid downwardly with the bottom free end of the lower base portion 11 striking the ear 20. A continual pressure downwardly at this point will cause the lower base portion 11 to flex circumferentially, permitting the lower base portion 11 to be slid thereover until the top edge 14 of the lower base .portion 11 which defines the bottom edge of the slot will sleeve member A from the inner sleeve member B without actually deforming same.

To insert an electron discharge tube into the shield construction it the outer sleeve member A is rotated until the opposed arm portions 12 and 13 are in mating relationship with the opposed arm portions 19 and 20 of the inner sleeve member B, giving accessibilty thereto by means of the opposed longitudinal slots. The tube D is then inserted in the socket by grasping the opposed side edges of the tube with the thumb and finger and pushing same downwardly into its socket, with the thumb and finger riding downwardly in the opposed slots. It Will be noted when the tube shield construction is in open position that the ear portion 20 engages the flange 16 of the arm portion 12 of the outer sleeve member Avto prevent its rotation to a point beyond that needed to bring the respective arm portions of the sleeve members A and B in registry or mating relationship with one another.

To provide the necessary shielding of the electron discharge tube, the outer sleeve member A is grasped along the flange portions 14 and 15 and rotated in a direction opposite to that employed for opening the tube shield construction 10. The outer sleeve member A is rotated until the flange portion 17 of the arm portion 13 carried by the outer sleeve member A strikes the protruding ear portion '21). At this point the opposed arm portions 12 and 13 of the outer sleeve member A will completely close the slots of the inner sleeve member B forming a complete tubular shield for the electron discharge tube.

It should be noted that in the illustrative form of the invention hereinbefore described, the inner sleeve member has been shown in fixed position with the outer sleeve member being rotatable relative thereto. However, it should be clearly understood that this is in no way to be construed as a limitation, since the reverse of this con- In this reversed form, the outer sleeve member will be in fixed relation and the inner sleeve member movable relative thereto.

While there have been described herein what are at present considered preferred embodiments of the invention, it will be obvious to those skilled in the art that modifications and changes may be made therein without departing from the essence of the invention. It is therefore to be understood that the exemplary embodiments are illustrative and not restrictive of the invention, the scope of which is defined in the appended claims, and that all modifications that come within the meaning and range of equivalency of the claims are intended to be included therein.

I claim:

1. A tube shield construction for shielding an electron discharge tube associated with a support comprising inner sleeve means, connecting means at one end of said inner sleeve means for securing same to a support in fixed relation thereto, the opposite end of said sleeve means being provided with a pair of diametrically opposed, free arm portions extending upwardly therefrom in generally longitudinal alignment therewith forming a pair of diametrically opposed longitudinally extending slots therebetween of a width sufiicient to enable the fingers of an operator to extend therethrough to grasp a tube positioned therein, rotatable outer sleeve means enveloping said inner sleeve means, the top portion of said outer sleeve means being provided with a pair of diametrically opposed, free arm portions extending upwardly therefrom in generally longitudinal alignment therewith forming a pair of diametrically opposed, longitudinally extending slots therebetween of a width sufficient to enable the fingers of an operator to extend therethrough to grasp a tube positioned therein, said inner and outer sleeve means being of substantially the same height and each having a substantially uniform diameter throughout their longitudinal lengths, said free arm portions of said inner and outer sleeve means being complementary with one another whereby upon rotation of the outer sleeve means the formed diametrically opposed slots in the inner sleeve means will be overlapped by the arm portions of said outer sleeve means to shield a tube positioned therein, stop means on one of said sleeve means to limit the rotation of said outer sleeve means, and retaining means to prevent the separation of said inner and outer sleeve means from one another.

2. A tube shield construction in accordance with claim 1 wherein the stopmeans is secured along a longitudinal edge of one of said arm portions of said fixed sleeve means.

3. A tube shield construction in accordance with claim 1 wherein the stop means holds the rotatable sleeve means in enveloping relation with said fixed sleeve means to prevent its longitudinal Withdrawal therefrom.

References Cited in the file of this patent UNITED STATES PATENTS 1,290,440 Wells Jan. 7, 1919 1,928,408 Clavier Sept. 26, 1933 1,980,183 Brosilow et al Nov. 13, 1934 2,019,939 Suller Nov. 5, 1935 2,080,913 Hafecost et a1. May 18, 1935

Images