US3402922A - Safety means - Google Patents

Description

Sept. 24, 1968 H. F. MCCAN 3,402,922

SAFETY MEANS Filed May 26, 1967 AGE/VT United States Patent 3,402,922 SAFETY MEANS Henry F. McCan, 2310 Ravina Curve, Upland, Calif. 91786 Substituted for abandoned application Ser. No. 593,759, Nov. 14, 1966. This application May 26, 1967, Ser. No.

5 Claims. (Cl. 2671) ABSTRACT OF THE DISCLOSURE -A telescoping protective shield for the tension springs of a garage door or the like wherein the shield may be readily applied to existing spring mechanisms and one or more plastic strips provide a guide for easy telescoping action.

This application pertains to a safety shield means for reciprocably enclosing counterbalance tension spring means secured to a slidable mounting of an overhead garage door or the like.

This application is a substitution for my application, Ser. No. 593,759, filed Nov. 14, 1966, to be later abandoned.

This invention relates generally to safety means for preventing the explosive scattering of fragments from spiral springs which break under tension. More particularly, the invention relates to such safety means adapted primarily for the shielding of powerful counterbalancing door springs of the type employed in many residential garages of recent construction to prevent fragment scattering in the event of spring rupture under tension.

Many residential garages, and particularly double garages, which have been constructed in recent years, and are being constructed today, have doors of the overhead swinging variety which are connected to their door frames through powerful counterbalance springs mounted either side of the latter. As will be understood by those familiar with such doors, and will be explained below, the aforesaid springs serve to counterbalance the rather substantial garage door weights in such fashion as to permit relatively easy opening and closing of such a door. Without going into a lot of detail here, the counterbalance springs are so installed on a garage door as to come under high stretching tension when the door is closed and to help pull the door to its open position after it has been moved partly in this direction by an upward and outward pull from a point near the bottom of its outer side.

Probably because of their recurrent subjection to stretching and relaxing movements in use, and their retent-ion for periods of varying duration under extreme stretching tension (when the garage door is closed), such springs sometimes reach'the breaking point. This invariably happens when the springs are under relatively high tension, with the result that metal fragments are released with great force inside the garage (since, as will be seen, the springs are so mounted as to be enclosed within the garage when the garage door is shut, or nearly so, and they are subjected to their greatest pulling forces). The released fragments fly through the air at high speeds, thereby posing a dangerous threat to anyone, or anything Within their range. Such fragments have been known to strike autornobiles with sufficient force to break windows, dent fenders or do other damage of a serious nature thereto; strike wooden garage beams with sufficient force to gouge deep holes therein; strike and break garage windows; and inflict other property damage of a like character. If the flying fragments can do this kind of damage to Wood, metal or safety glass of the type used in car windows, they are sufliciently dangerous to pose a serious threat to the safety, and even life, of a person unfortunate enough to be trapped inside a garage when one or more of its counterbalance springs gives way. This danger is particularly acutewhen one has a home with a connecting garage in which he habitually parks his car and closes the garage door from the inside before proceeding into the house, since in this case he is fully exposed to the danger of spring breakage shrapnel from the time he closes the garage door until such time as he enters his house.

I have now improvised telescoping safety means for preventing the explosive escape of fragments from a spring which breaks under tension in the above-described manner. In its preferred form, the safety means comprises a pair of shield members designed for quick and easy emplacement around springs of the above-described type after installation of the latter for garage door counterba'lancing, or equivalent service. The shield members are designed to completely enclose springs around which they are so emplaced and thereafter work telescopically together to permit elongation and contraction of the resulting spring shield as the springs are stretched and relaxed in service.

It is thus a principal object of this invention to provide safety means for preventing the explosive release of flying fragments of spiral tension springs when they rupture under tension.

It is another object of the invention to provide such means particularly suitable for the prevention of such release of fragments from springs of the type employed for the counterbalancing of garage doors of the overhead swinging type when such springs break under tension, thereby obviating any possibility of personal injury and/ or property damage by the fragments.

It is another object of the invention to provide such safety means adaptable for quick and easy emplacement for the prevention of explosive fragment release from garage door springs of the above-indicated type after the latter have been installed for service.

In summary: This invention pertains to a safety telescoping cover means for tension spring and the like associated with overhead mounted garage doors having counterbalanced springs. Exposed tension springs in such installations represent a safety hazard to operating personnel thereof, due to possible scattering of broken spring fragments, should the tension springs disintegrate during use. The new safety telescoping cover means of this invention are easily assembled over the springs after the springs are installed.

In one aspect of the invention, the cover or shield members comprise a pair of telescoping tubular members made from a pliable metallic or plastic material shaped to fit around springs subjected to tension and having a longitudinal'ly extending slit or separation permitting ready application of the shields to existing spring mechanisms. The telescoping shields are provided with outstanding flanges or lugs at the separation slits and easily applied fastening means such as bolts provide for clamping the guard members in surrounding relationship with respect to the spring mechanism. Suitable means such as bolts passing through distal portions of the spring mechanism provide for ready attachment of the telescoping shields to the spring mechanism. One or more plastic tabs or strips of plastic material are preferably inserted between the lugs or flanges of the inner shield to provide bearing guides and permit easy telescoping action.

The new telescoping cover members are easily made from molded plastic, sheet metal or the like.

The new safety telescoping cover means of the present invention is safe, economical to manufacture and easy to install by unskilled tradesmen.

Other objects, features and advantages of the invention -will be more readily understood in the light of the following description considered conjunctively with the accompanying drawing showing preferred embodiments of the safety means of the invention, of which;

FIGURE 1 is a side elevation of a pair of garage door counterbalance springs installed at one side of the door and encased in an enclosing embodiment of the safety means of this invention, the garage door being shown fragmentarily and in its closed position whereat the counterbalance springs are in their stretched, or extended, positions.

FIGURE 2 is a side elevation of the FIGURE 1 garage door, springs and spring-encasing safety means, but with the garage door shown in open position whereat the springs are in their fully relaxed positions.

FIGURE 3 is an enlarged view of the springs and safety means of FIGURE 1, a part of the latter being broken away at the top to show the manner in which the springs are connected to a spring holding member of a mounting assembly therefor.

FIGURE 4 is a still further enlarged cross section of the springs and their encasing safety means, taken along line 44 of FIGURE 3.

FIGURE 5 is a longitudinal sectional view of a modified form of the safety means of this invention installed within a mounted spiral spring of the type shown in FIG- URE 3, the spring being shown in tension and its coils being partially symbolically represented by means of phantom lines.

Considering now the drawings in greater detail, there is shown generally at a spring-controlled door operating mechanism of the type commonly employed for the operation of garage doors of the overhead swinging variety referred to above. Door operating mechanism 10 comprises a bracket plate 14 mounted on the door frame, the latter being shown at 13 and hereinafter referred to as door frame 13; a spring tension bar 16 (pivotally mounted on bracket 14, as shown at 17); an angle iron bracket 20, mounted on the door (shown at 21, and hereinafter referred to as door 21); a plate-like bracket 24, fixedly secured to angle bracket by rivet means and in outstanding relationship to said door, all as shown in FIGURES 1 and 2; a strut member 22 pivotally secured at its ends to plate bracket 14 and outstanding bracket 24, respectively, as shown; a link 18 pivotally connected at one end to the first end of tension bar 16, and receptive of a double hook 26 at the other end, in the manner shown in FIGURE 3, to which the upper ends of a pair of spiral tension springs 12 (comprising a part of the door operating mechanism, and described in greater detail below) are attached; a short length of chain 23 fastened by staple means at a lower end to door frame 13 at a point near the floor of the garage, as shown in FIGURES 1 and 2, and having its upper end link looped around a second double hook member 26 connected to the bottom ends of springs 12 in the manner shown in the drawings, and particularly FIGURE 3; all parts of the door operating mechanism being designed and installed to permit opening and closing of the door in the manner described below.

Door operating mechanism 10, as will be appreciated, constitutes only one half of the overall control assembly for door 21 and it has a mirrow image counterpart which is installed at the opposite side of door frame 13 from that shown in FIGURES 1 and 2. The latter is omitted from the drawing because it is of essentially the same construction as operating mechanism 10, and because, as will be seen, the door control assembly per se constitutes no part of this invention and is of a type well known to all familiar with overhead swinging doors of the here-involved type.

Briefly, door operating mechanism 10 makes it possible to swing door 21 between a completely closed position, as illustrated in FIGURE 1, and a completely open position, as illustrated in FIGURE 2. For obvious reasons,

the door operating mechanism is installed on the inward side of the door and door frame, or to the left of the door in its FIGURE 1 position of complete closure. Consequently, when the door is closed the operating mechanism is hidden behind it, inside the garage or other area protected by the door. It will be noted that the pair of springs 12 is stretched and compressed as the door moves between its open and closed positions, reaching a point of extreme tension in the door-closed position illustrated in FIGURE 1, and of complete relaxation in the dooropen position illustrated in FIGURE 2. While the springs themselves do not appear in FIGURES 1 and 2, it will be evident from the appearance of a telescoping cover, or shield, 27 completely surrounding the pair of springs, and hereinafter described in detail, in the door-closed and door-open positions of the springs that the latter are in their extreme positions of tension and relaxation coincidentally with their door-closed and door-open positions, respectively.

As FIGURE 1 makes clear, the complete closure of door 21 results in such positioning of tension bar 16 as to cause it to incline steeply upwardly from its pivotal connection with angle iron bracket 20 on the garage door, the angle of the tension bar thus being such that its inner end is at an elevation sufiicient to exert substantial stretching pull on springs 12 through link 18, thereby causing elongation of the springs as shown. The door is opened by pulling it outwardly and upwardly by a handle attached to its outer side near the bottom, not shown, and pivoting it around the mounting point 17 of tension bar 16 on bracket 14, until the bar is substantially vertically disposed in the manner shown in FIG- URE 2. As will be apparent, springs 12 exert a pulling influence on the bar 16 after it reaches a certain point in its pivotal movement to aid in movement of the door to its overhead, or open, position. As the door swings into its open position, strut 22 is maneuvered into the rigidly bracing position shown in FIGURE 2, thus providing a brace to help hold the door open.

To close the door, its outer bottom edge, that to the right in FIGURE 2, is pulled downwardly, against the tension of springs 12 which are stretched as tension bar 16 is again pivoted around its mounting point on bracket plate 14 toward the position shown in FIGURE 1. When the door is past a certain point in its swinging movement, its weight overbalances the pull of the springs 12 and it rides to the closed position of FIGURE 2. It goes without saying, that the counterpart of operating mechanism 10 installed at the opposite side of the door frame opening from that shown in the drawing goes through a series of mechanical movements the same as, but in mirror image unison with, the above-described movements of operating mechanism 10 as the door is opened and closed.

As will be apparent from the foregoing, door operating mechanism 10 is of a type intended primarily for use on heavy doors such as, for example, the heavy wooden doors of double garages of the sort found in modernly constructed homes, and its component parts must therefore be of sufliciently sturdy construction for dependable service under these circumstances. Typically, such parts are made of steel, with the spring members, corresponding to springs 12, being made of a tough spring steel in lengths of 28, 30 or 36 inches to provide a range of sizes for doors of varying sizes and weights. Even so, there is an inherent danger of spring breakage, with the dangerous and/or damaging consequences referred to above, in the normal usage of such springs. In this connection, I have personally experienced property damage from flying fragments of springs similar to springs 12 which have broken in my garage and am aware of a number of other instances of such spring breakage and consequent property damage.

Door operating mechanism 10 has been described in considerable detail above, although it forms no part of the present invention, in order to highlight the principal problems solved by the invention, namely, the danger of counterbalance spring breakage, and consequent injury or damage to surrounding persons or property, under the substantial stresses to which such springs are subject in use. Since, as previously indicated, door operating mechanisms of the described type are well known, further discussion of the structural and operational details of operating mechanism 10, other than as necessary to demonstrate the utility of the safety means of this invention in its protective capacity relative to springs 12, will be omitted.

The present invention, in its preferred form, is simply a longitudinally extensible shield or cover for springs such as springs 12, which are liable to rupture under tension in use. Very simply, the shield is so designed and positionable for use as to intercept any flying fragments resulting from such spring rupture and keep them from doing harm to otherwise vulnerable persons and/or objects. Illustrated at 27 is a preferred embodiment of my spring shield or cover hereinafter referred to as spring shield 27. Spring shield 27 consists of a pair of telescoping tubular elements, the larger of the two being shown at 28, and hereinafter referred to as upper shield member 28, and the smaller being shown at 30, and hereinafter referred to as lower shield member 30. As will be apparent from the above terms, the larger of the shield members encases the upper part, and the smaller the lower part, of the spring in its drawing-illustrated position.

The shield members, as the drawing shows, cooperate to surround the two springs 12 substantially completely even to side enclosure of two pairs of rings, or eyes 12a and 12b, forming the respective top and bottom termini of the springs. In this'connection, springs 12 are each conventionally configured with a round ring or eye extending longitudinally from each end of its spiraled body portion in the manner illustrated in FIGURE 3.

The upper and lower parts of spring shield 27 are each made of a thin metal material capable of being easily formed into the desired shape such as, for example, galvanized iron or aluminum sheet stock. Each is of tubular shape, oval cross section and adequately sized to permit its encirclement of springs 12 with room to spare and, in the case of upper shield member 28, to permit a sliding interfit of the lower shield member therewithin, all as illustrated in the drawing, and particularly FIGURE 4. Each of the shield members is formed from a single piece of flat metal in such fashion as to have a pair of opposite edges which terminate in outstanding flanges running longitudinally of the shield member in its completed form and designed to meet flush and provide a seam readily securable by bolt-and-nut, rivet, or equivalent fastening means. These flanges are shown at 28a on upper shield member 28 and at 30a on lower shield member 30, and will be hereinafter referred to as flanges 28a and 30a, respectively. Flanges 28a are fastened together by a plurality of bolt-and-nut fastening means 32 and flanges 30a by a similar plurality of such fastening means 34.

Neither flanges 28a nor 30a run the full length of their respective shield members. There is no particular criticality to the illustrated flange lengths, however, and the shield member flange lengths can vary therefrom within the scope of this invention so long as they are adequate to permit edge fastening of each member together in such a way as to provide a spring shield of the herein-described type. In this connection, and as will subsequently appear, the shield member flanges must, in certain instances, be somewhat limited in length to prevent their interference with door frames, or operating mechanism parts, adjacent, or in working combination with, the springs the shield members are intended to encase.

As will be clear from the above description of the manner of assembly and functioning of door operating mechanism 10, the two tension springs 12 are mounted narallelly on corresponding outer hook portions of the two double hooks 26, which hook portions are linked with the upper and lower eyes 12a and 12b, respectively, of the springs in the manner illustrated in FIGURE 3. This manner of mounting the springs is well known in door operating mechanisms of the illustrated type, and needs no further discussion here except, perhaps, the comment that all parts of the involved assembly are so mounted as to assure suflicient tension on, or support of, the springs by the double hooks to keep the former tightly snugged against the hooks at all times, even when the springs are relaxed in the door-open position of FIG- URE 2.

Upper shield member 28 is supported around springs 12 by a pair of bolts 36 which run completely through the two sides of the shield near the top of the latter. The bolts pass through the upper eye 12a of the springs, respectively, and are fastened in place by a pair of nuts (not shown on the drawing) tightened snugly on the far ends of the bolts against the outer wall of the upper shield member. As FIGURE 3 shows, the upper shield member pulls down on the two bolts 36 which thereby serve to support the shield member in partially, but not freely, hanging relationship. Similarly, two bolts 38 pass through the sides of lower shield member 30 and eyes 12b at the lower ends of spring 12, respectively, to be fastened in place by nuts at their far ends, as viewed in FIGURES 1, 2 and 3. Bolts 38, however, unlike bolts 36, serve to support the down-bearing, rather than hanging, weight of the shield member through which they pass.

The lengths of the two shield members are such as to permit the substantially complete telescoping of the lower within the upper one when the springs are in their relaxed positions, as illustrated in FIGURE 2, yet permit extension of the spring shield far enough to surroundingly accommodate the springs when they are stretched to their fullest extreme, as illustrated in FIGURE 1. As FIG- URES 1 and 3 show, the lower shield member is positioned with its flange strips 30a facing outwardly from the door frame, whereas the upper shield member has its flange strips facing oppositely, or towards the door frame. This is not a critical flange orientation, except in the sense that in the illustrated use environment it prevents jamming of the outstanding flange strips of the lower shield member against the door frame because of the proximity of the lower ends of springs 12 thereto, particularly when they are relaxed, as shown in FIGURE 2. Inthis connection, the shield members can, if desired, be fitted together with their flange seams facing in the same direction, or oppositely to the directions they face in the drawing, so long as they are free to telescope in the manner taught herein.

Upper shield member 28 has a notch cut 28b at the upper end, and a second notch cut 28c at the lower end, of its flanged side. The purpose of these notches is to provide accommodating room for relative approach of the operating mechanism or door frame as the springs move through the above-described series of stretching and relaxing movements during normal usage of door 21. The upper notch 28b is, where needed, of benefit only during the final phases of the spring stretching movement as the door rides to its closed (FIGURE 1) position. While, in the latter connection, notch 28b is obviously unnecessary in the drawing -illustrated version of an installed and operative spring shield in accordance with this invention, there are other circumstances of spring shield installation and use in which a door operating mechanism part, such as, for example, that corresponding to bracket 14 of operating mechanism 10, would so conflict with the shielded door springs when the door is closed as to require a notch correspondent to note-h 28b in the spring shield to prevent jamming between the shield and part at such times.

The bottom notch 280 in upper shield member 28 serves to provide space for the edge of door frame 13 when door 21 is in the open position illustrated in FIGURE 2, and the lower portions of the springs are, as a result, drawn close to the door frame coincidentally with a lowering of 7 the upper shield member to adjacency of its lower end with the lower ends of said springs as the latter assume their relaxed, open-door, positions. A comparison of FIG- URES 1 and 2 will serve to make clear the correlation between the spring 12 movements and the relative nearness of upper shield member 28 to an interfering part of the door operatingmechanism or door frame 13. Lower shield member 30 has a notch 30b at its lower end on the side facing the door frame which serves substantially the same purpose as the lower notch 280 of upper shield member 28.

Wedged between flange strips 30a of lower shield member 30 at the sites of bolt-and-nut fastening means, or fasteners, 34 are a plurality of plastic guide tabs 40, each tab being of square shape, having a hole through the center to receive the bolt of a fastener 34, and being of suflicient size to permit an edge to extend slightly beyond the outer edges of flange strips 30a in the manner shown in FIGURE 4. The plastic guide tabs 40 provide a relatively slick hearing surface between the upper and lower shield members to permit smooth and comparatively soundless riding of the latter within the former. Such guide tabs are not critically necessary to proper usage of my spring shield, but they greatly improve its quality of operation. It is not necessary that there be a tab at every bolt-and-nut fastener site along flange strips 30a, and there can be such tabs at fewer than the total number of sites down to, and including, only one, which would preferably be the top one on the shield member. In this connection, it is, of course, desirable to locate the guide tab, or tabs, in such manner as to minimize the possibility of cocking, .and consequent jamming, of the lower shield member in the upper one.

There is nothing magic about the particularly illustrated number of bolt-and-nut fasteners on the outstanding flanges of either upper or lower shield member 28 or 30, respectively, and any number of such fasteners adequate to hold the mating flanges of each member together will suffice for purposes of this invention. Where the spring shield is made of galvanized iron, or other relatively hard metal, fewer fasteners will suffice than where it is made of a softer metal such as aluminum. Illustratively, hard metal shield members of suitable size for use on typically representative garage door springs can, I have found, be adequately secured at their seams with three flange fasteners. While shield members of the same size, but made of sof-ter metal, can also be secured with three such fasteners, five are, at least in many cases, preferable under these circumstances.

A principal advantage of my spring shield invention, as will be appreciated, is that it lends itself to quick and easy installation around operating garage door, or spring-em bodying mechanism or apparatus. Because of this, it is unnecessary to encase the springs in the shield at the factory, or elsewhere, although this can, of course, be done within the scope of my invention. More to the point, the homeowner himself can install such .a shield around his existing garage door springs with a minimum of difficulty, and little more than a few seconds time, even if he has little or no mechanical ability. To make such an installation, it is only necessary to fit the separate (lower and upper) members comprising the shield around the springs to be covered, the lower, or smaller, one first, and fasten the seam flanges of each together, these steps being, of course, performed in proper sequence to accomplish the purpose. As the final step of the installation procedure, the bolts which pass through the eyes at the ends of the springs are properly inserted through the shield member walls and spring eyes and tightened in place with lock nuts, or the equivalent.

The above-described installation procedure is specific to the installation of a spring shield conforming to illustrated spring shield 27 in design and it will be :understood that guide tabs equivalent to illustrated guide tabs 40 can be properly fastened in place in the flange seam of the lower shield member as a part of the overall installation procedure. It will also be understood that the described procedure must be repeated for the shielding of each of the two pairs of counterbalance springs in the homeowners garage if he is to have complete protection from spring breeakage hazards. In any event, after the installation of a springshield in accordance with present teachings, the springs in question are completely surrounded by a protective barrier and the homeowner land the contents of his garage are safe from flying fragments in the event those springs should break.

FIGURE 5 shows at 42 an alternate form of the safety means of this invention intended for use in the hollow center of each of, rather than in surrounding relationship to both of, springs 12, hereinafter referred to as telescoping unit 42. Telescoping unit 42 comprises a lower rod s'egment 46 and an upper tubular segment 44, each being of round cross section and sized to permit snugly sliding interfit of the former within the latter, in the manner illustrated in FIGURE 5. The two parts of the telescoping unit 42 are so sized as to remain relatively rigid during all phases of stretching elongation of springs 12, yet telescope together to a sufficient extent to fit the shortened length of a spring 12 in the relaxed, or open-door, position of FIGURE 2.

Telesco ing unit 42 is adapted to fit inside one of springs 12 and it has a pair of relatively flexible metal strips 48, each attached at one end to the upper edge of tubular member 44 of the unit and extending diametrically across the upper end of that member, in a direction substantially opposite to that of the other strip, for a sufficient distance to permit its looping fit over the bottom part of the upper eye of a spring in which the tubular member is installed and consequent provision of support for that member, all as illustrated in FIGURE 5. Rod member 46 of the telescoping unit has a flexible metal strip 50, similar to one of strips 48 of the tubular member of the unit, attached to its bottom end, as viewed in FIGURE 5, in such fashion, and of such size, as to provide a finger-like means for gripping the base of the lower eye of a spring in which the telescoping unit is installed, all, again, as illustrated in FIGURE 5.

In the latter connection, rod member 46 really needs nothing to hold it at its proper operating level within a spring such as illustrated in FIGURE 5 since, as will be apparent, its lower end rests on the base of the springs lower eye to keep it (the rod member) so positioned. The use of strip 50 of the rod member in the above-described, and drawing-illustrated, fashion, therefore, serves in no way to hold the rod member up, but merely to keep it contered within spring 12, or its equivalent, and substantially aligned with tubular member 44, whereby telescoping unit 42 can function to best effect, and with minimal possibility of malfunction as a result of contact with the spring or misalignment of its parts, during the normal stretching and contracting movements to which the spring is subjected in use.

Since telescoping unit 42 fits inside one of its springs 12, two such units are required for the complete protection of operating unit 10 against spring breakage and fragment loss. It will be understood, of course, that an additional pair of the units will be required for the operating unit springs at the opposite side of the garage door. Telescoping unit 42 alfords a certain degree of protection, although not as much as shield 27 does, against spring fragment loss, since a garage door tension spring generally breaks, I have observed, in such a way as to leave fragments individually comprising at least one complete spring coil.

This being so, all fragments from an average break will completely encircle a telescoping unit installed in the broken spring and therefore be prevented from flying through the air. It is, of course, remotely possible that smaller fragments than those discussed abovecan result from a spring break, in which casev telescoping unit 42 might be less effective than shield 27 inpreventing damage since the latter intercepts and traps all flying fragments (regardless of size) from such a break.

It is within the scope of my invention to employ telescoping units 42 alone, spring shields 27 alone, or combinations of the units and spring shields in any given use situation for which either of those embodiments will suffice. In this connection, however, the spring shield embodiment of my invention is, for reasons given or made plain above, generally preferable for use to that exemplified by telescoping unit 42.

It is within the scope of this invention to install telescoping unit 42 in the FIGURE spring with its rod member, rather than its tubular member, up (or the reverse of the way it is installed in FIGURE 5). Where this is contemplated, however, it would, for obvious reasons, be preferable to substitute for the telescoping unit a modified form thereof having two fastening strips on its rod member and one fastening strip on itstubular member in lieu of strip 50 and strips 48, respectively, of the former (telescoping unit 42). Sufiice it to say in this regard, that the embodiment of my invention exemplified by telescoping unit 42 can have any means for fastening it in place within a spiral tension spring in such fashion that it telescopes outwardly and inwardly as the spring stretches and contracts and remains sufficiently strong at all times to prevent broken spring fragments from flying in the event the spring ruptures under tension. In this connection, it is within the scope of the invention to employ two tubular telescoping members, rather than a solid and a tubular one as shown in the drawing, for this embodiment of my invention.

What has just been said relative to the reversal of position of telescoping unit 42, or its equivalent, within spring 12, is also true with respect to spring shield 27, that is, the shield can be installed with its smaller, and heretofore referred to as lower, member covering the upper portions of springs 12, and its larger, and heretofore referred to as upper, member covering the lower portions of the springs, or oppositely to the way those parts are oriented in FIG- URE 3. Likewise, the spring shield can be installed with only one bolt 36, or its equivalent, through one of the upper spring eyes 12a, rather than with bolts through both eyes in the illustrated fashion. It is preferred to employ two bolts, however, since this provides insurance of shield retention in the event one of the springs breaks in such fashion as to release upper shield member 28, thereby exposing the surroundings to the danger of possible breakage of the other spring. There is not the same urgency about having the two bolts 38 through the two lower, as there is for having the bolts 36 through the two upper, spring eyes, and one of the two can be dispensed with no great loss since the lower shield member will never slide completely out of the upper shield member, even in the event both of springs 12 should break, but will, at most, drop to a point at which it makes contact with door frame 13, after which the latter prevents it from dropping any further and holds it in place not far from its normal operating position.

While the safety means of this invention have been herein illustrated and discussed primarily in terms of reference to a specialized utility in association with pairs of garage door springs of a commonly known type, it will be apparent that the safety means are not so limited in serviceability and can be employed associatively with other springs which are subject to repeated stretching in use and potentially harmful to their surroundings if they rupture while under tension. In this connection, the safety means can be tailor-made for use conjunctively with a single tension spring, rather than a pair of springs such as those illustrated in the drawing, intended for door counterbalancing, or any other, applicability in which it is subject to repeated stretching tension and consequent danger of breakage.

The present invention has been described in considerable detail in order to comply with the applicable patent law provisions by providing a full public disclosure of at least one of its forms. Such detailed disclosure is not, however, intended to in any way limit the broad features or principles of the invention, or the scope of patent monopoly sought to be granted. Accordingly, while the invention has been herein illustrated and described in what are conceived to be preferred and practical forms, it is emphasized that departures may be made therefrom within the scope of the invention. Certain of these-departures have already been mentioned, and others will occur to those skilled in the art in the light of present teachings. Exemplary of the latter are noncritical variations of the shapes of various parts of the subject safety means; the elimination of certain structural, or other, features of any of said safety means not critically essential to proper use and functioning thereof; the addition of useful, but noncritical, accessories to the safety means; etc.

As a specific example of the kind of modification contemplated above, a strip of plastic could be fastened between flange strips 30a of shield member 30 of spring shield 27, in lieu of plastic tabs 40, if desired. Such a plastic strip would, of course, be preferably so sized and positioned between the flanges of the shield member as to present a continuous edge for sliding contact with the inner wall of the shield member 28 as the latter works up and down around shield member 30 during normal usage of door operating mechanism 10.

It is emphasized, in final summary, that the scope of my invention extends to all variant forms of its drawing-illustrated embodiments encompassed by the language of the following claims.

I claim:

1. In a tensioned spring mechanism such as utilized in the opening and closing of garage and other doors and wherein coiled spring means are repeatedly placed under substantial tension, a readily attachable shield means for guarding against damage due to fragmentation of said spring means, said shield means comprising a pair of telescopic members made from pliable sheet material and having a shape adapted to surround said spring means, said members having a longitudinally extending separation slit at one side to permit application to said spring means, and means for securing said members together at said separation slit.

2. A guard shield for a tensioned spring mechanism as defined in claim 1 in which readily accessible holding means adjacent the distal portions of said telescoping shield members provide for attaching said shield members to said spring mechanism.

3. A guard shield for a tensioned spring mechanism as defined in claim 2 wherein guide means comprising a plastic sheet of material is supported in one of said telescoping members at said longitudinally extending separation slit.

4. A guard shield for a tensioned spring mechanism as defined in claim 3 in which said telescoping shield members have outstanding flanged lug means, said securing means extends through said lug means, and said guide means is clamped within said flagged lug means.

5. A guard shield for a tensioned spring mechanism as defined in claim 4 wherein said guide means comprises a sheet of plastic material extending longitudinally of one of said telescoping members at said separation slit.

References Cited UNITED STATES PATENTS 1,826,647 10/1931 Blodgett 191 2,129,338 9/1938 Timmons 26774 X 2,806,722 9/ 1957 Atkins 287-58 3,004,743 10/ 1961 Wenger 287-58 FOREIGN PATENTS 166,899 2/ 6 Australia.

245,782 3/ 1966 Austria.

409,691 10/1966 Switzerland.

DAVID J. WILLIAMOWSKY, Primary Examiner. DENNIS L. TAYLOR, Examiner.

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