US1922370A - Door construction - Google Patents

Description

ug.15,19331. 'CQQJOHNSON ML 1,922,370

` DOOR CONSTRUCTION,-

Filed Aug.' 4. 1951` 2 sheets-sheet 1 l 2 gNvENTon A ATTORNEYS .`Aug.1s,1933.` c aJoHNsoNET AL 1;922,370

Doo CONSTRUCTION ATTORNEYS Patented Aug. `15, 1933 PATENT OFFICE D001! CONSTRUCTION Clarence G. Johnson and Herbert C.

Hartford City, Ind., assignors to Blodgett, Overhead Door Corporation, Hartford City, Ind., a Corporation of Indiana Application August 4, 1931. sensi No. 555.108

The present lnventionpertains to a novel counterbalancing system for sliding doors particularly of the type wherein the door in opening moves first along a vertical track section and then onto a horizontal track section.

The principal object ofthe invention is to provide a device of this character especially applicable to installations where the vertical track section extends a considerable distance over the topof the'door opening, orin other words, where the clear space to the ceiling must be considerably higher than the door opening. A structure of this type may, for example, be a greasing station or repair shop where the automobile is lifted off the iioor.

In installations Where the vertical track section is substantially as high asl the door opening, the problem of counterbalancing the door is comparativelyv simple, inasmuch as the effective, weight of the door commences to diminish immediately it is raised and the tension oi the counterbalanced spring also commences to diminish at the same time.V However, in cases where the vertical track section is higher than the door opening, the door does not commence to lose its effective weight immediately but only when it begins 'to ride on the horizontal track section, while the tension of the counterbalance spring on the other hand begins to diminish immediately. f

The object of the invention, specifically, is to provide a counterbalancing system 'which meets this difilcultyor in other words, maintains a substantially constant relation between the counterbalance spring and the effective weight of the door at all times. This object is accomplished generally by the use of cables wound on drums carried by a spring-tensioned shaft, the drums having a combination of conical and cylindrical portions so related that the effective radius oi' the conical portion varies while the door is entirely in the vertical track section, thereby compensating for the constantly changing tension of the spring although the unsupported weight of the door does not change.

A further object of the invention is to provide'a compensating device which does away with the necessity of accurately winding the cables on their respective drums. Still another object is to provide safety means to prevent dropping of the door under its own weight in the event that the counterbalance spring should break.

The invention is fully disclosed in the followingdescription, by way of example, and in the accompanying drawings in which- 1t) Claims. (Class 20-20) 65 Reference to these views will now be had by use of like characters which are employed to designate corresponding parts throughout.

A door frame l is built in any desired manner in a garage or other structure and presents a door opening 2 to be closed by a door of the hinged panel type. It will be seen that the building structure is considerably higher than the door opening.- A track consisting oi' a pair oi rails is provided at the door opening, and each rail has a substantially vertical portion 3 extending considerably above the door opening and a substantially horizontal portion 4 extending rearwardly or inwardly from the upper end of the vertical portion. The door consists of superimposed panels 5 joined together by hinges 6 on horizontal axes. The hinge pintles 7 carry rollers 8 riding in the tracks in the manner now well known in the art.

In the opening oi' the door, the latter first rides completely on the vertical portions 3 luntil the upper panel moves onto the horizontal portion 4. Thus, the unsupported weight of the door remains constant until the door commences to ride on the horizontal portion 4, after which the unsupported weight gradually diminishes. This type of construction is suitable especially for buildingshaving a comparatively large height, as already indicated, and one example of such a structure is a garage or repair shop in which an automobileis lifted oil` the iloor forservice or repair work thereon. The height of the door opening 2 is slightly greater than that of an automobile.

A shaft 10 for carrying a counterbalanclng means and cable drums for the door is rotatably supported in a convenient position, preferably directly over the door opening and parallel to the upper edge of the door, in bearings 11. The ends of the shaft carry drums, each having a conical portion 12 and a cylindrical portion 13 for a purpose which will presently be described. The drums have cables 14 wound thereon, preferably in thread grooves 15 provided for the' purpose o! ensuring uniform winding and unwinding.

Each cable has its free end connected to a bracket 16 at the lower corner of the door, preferably through the medium of a coil spring 17. To each bracket is secured a stop member 18 looped as at 19 around the adjacent cable and directly over the corresponding spring 17. The loop or eye 19 is of such size that the spring 17 cannot pass therethrough in case that it should break, so that the free end of the cable is nevertheless retained by the stop member if such breakage of the spring should occur. e

A torsional spring 20 surrounds the shaft 10 and has a plug 21 threaded into one end thereof and keyed as at 22 to the shaft. The other end is free of the shaft but has a similar plug 23 threaded therein and equipped with a stop finger 24 secured thereto by' bolts 25. Adjacent this end of the spring, a bracket 26 is secured to the structure 1 and has an arm 27 pivoted thereto by a stud 28. This arm is engaged by the stop nger 24 under the tension of the spring. It Will be seen that the arm 27 is of considerable length so that the finger may slide along the same as the spring contracts or elongates on lowering or raising of the door. The spring may be adjustably tensioned for properly counterbalancing the door by detaching the finger 24 and turning the plug 23 by a suitable tool inserted in apertures 29 formed in the plug. For the same l' purpose of adjustment, the finger 24 has av seriesv of bolt holes 30 for connecting the finger 24 in various 'angular relations to the plug.

The cables 14 are connected to the door in such a manner as towind rst on the conical portions and then on the cylindrical portions as the l 20 gradually loses its tension from the time the lifting movement is commenced. During the initial lifting movement of the door, however, the effective radius or leverage of each drum is diminished as the cable winds towards the cylindrical portion. The conical portion of each drum is so dimensioned that the diminishing effective radius compensates the diminishing tension of the spring, whereby the spring main-i tains a proper counterbalancing relation to the door until the latter reaches the horiontal portion 4 of the track.

As the door commences to ride on the horizontal portion of the track, its effective or unsupported weight gradually diminishes. It will also be recalled that the tension of the spring gradually diminishes. Consequently, the conical portion of each drum is constructed to function only until the door reaches the horizontal track section. In other words, the cable-thread of each conical portion has a developed length substantially equal to the difference between the height of the vertical track portion 3 and the height of the door. As the door commences to ride on the horizontal track section, the cables Wind on the cylindrical parts of the drums, so

that there is no variation in the effective radii of the drums.' The spring 20 is so constructed that it loses its tension in proportion to the rate at which the door loses its effective or unsupported weight as it rides over the horizontal track section.

As the door is closed or lowered, it will be evident that these conditions are relatively reversed, although the balancing action of the spring 20 'with respect to the unsupported weightl of the pawl has a fork 34 straddling the arm 27 whereby the ratchet is normally held out of engagement with the pawl. A spring 35 tends to throw the pawl towards the ratchet but is resisted by the tension of the spring 20 acting on the arm 27 through the medium of the nger 24. In the event that the spring 20 should break, the spring 35 is rendered free to throw the pawl into engagement with the ratchet, although swinging the pivoted arm 27 which is now unresisted. Thus, the door is prevented from dropping under its own weight in the event that the spring 20 breaks. The door is also rendered safe against breakage of the spring 17 by the stops 18 and eye 19 as previously described.

With reference again to the drums, it will be evident that the cables must ordinarily be accurately wound thereon, for otherwise one cable would be on the conical portion while the other would be on the cylindrical portion, as a result of which oney cable would be fed or wound at a greater rate than the other cable, thereby tending to move the ends of the door at different rates and consequently tilting the door to bind it in its track. The spring 17 however overcomes the necessity for such accurate setting of the cables. Any unequal winding or feeding of the cables under the conditions described causes a stretching of the spring 17 at the end of the door Which tends to be pulled upwardly with respect to the other end, whereby the effect of the unequal winding or unwinding is at least substantially overcome.

Although a specific embodiment of the invention has been illustrated and described, it will be apparent that various alterations in the details` of construction may be made without departing from the scope of the invention as indicated by the appended claims.

What We claim is:-

1. 4In combination with a vertically and horizontally slidable door, a track guiding said door and having a vertical portion longer than the height of the door and a substantially horizontal portion extending from the upper end of the vertical portion, a rotatable shaft, a torsional spring surrounding said shaft and having one end secured to the shaft, stop means for the other end of said spring, a drum on said shaft having a conical portion and a cylindrical portion, and a cable extending from said drum and secured to said door and positioned to wind first on the conical portion and then on the cylindrical portion as the door is raised.

2. In combination with a vertically and horizontally slidable door, a track guiding said door and having a vertical portion longer than the height of the door and a substantially horizontal portion extending from the upper and of the vertical portion, a rotatable shaft, a torsional spring surrounding said shaft and having one end secured to the shaft, stop means for the other end of said spring, a drum on said shaft having a conical portion and a cylindrical portion, and a cab e extending from said drum and secured to said or and positioned to wind rst on the conical portion and then on the cylindrical portion as the door is raised, said conical portion being so dimensioned that the cable and wind- 3. In combination with a vertically and horizontally slidable door, a track guiding said door and having a vertical portion longer than the height of the door and a substantially horizontal portion extending from the upper end of the vertical portion, a rotatable shaft, a torsional spring surrounding said shaft and having one end secured to the shaft, stop means for the other end of said spring, a drum on said shaft having a conical portion and a cylindrical portion, and a cable extending from said drum and secured to said door and positioned to Wind first on the conical portion and then on the cylindrical portion as the door is raised, the cable-thread on the conical portion having a developed length substantially equal to the difference between the length of the vertical portion of the track and the height of said door.

4. In combination with a vertically and horizontally slidable door, a track guiding said door and having a vertical portion longer than the height of the door and a substantially horizontal portion extending from the upper end of the vertical portion, a rotatable shaft, a torsional spring surrounding said shaft and having one end secured to the shaft, stop means for the other Yend of said spring, a drum on said shaft having a conical portion and a cylindrical portion at the smaller end of the conical portion, and a cable extending from saiddrum and seciired to said door and positioned to wind rst on the conical portion and then on the cylindrical portion as the door is raised.

5. In combination with a vertically and horizontally slidable door, a track guiding said door and having a vertical portion longer than the height of the door and a substantially horizontal portion extending from the upper end of the vertical portion, a rotatable shaft, a torsional spring surrounding said shaft and having one end secured to the shaft, stop means for the other end of said spring, a drum on said shaft having a conical portion and a cylindrical portion at the smaller end of the conical portion, and a cable extending from said drum and secured to said door and positioned to wind rst on the conical portion and then on the cylindrical portion as the door is raised, the cablethread on the conical portion 'having a developed length substantially equal to the difference between the length of the vertical portion of the track and the height of said door.

6. In combination with a vertically slidable door, a shaft parallel to the upper edge of said door, a single counterbalance means acting on said shaft, drums on the ends of said shaft, cables wound on said drums and connected to said door, and springs inserted in said cables.

7. In combination with a vertically slidable door, a shaft parallel to the upper edge of said door, a single counterbalance means acting on said shaft, drums on the ends of said shaft, cables wound on said drums, springs connecting said cables to said door and stop members carried by said door and having eyes looped around said cables adjacent said springs, said springs being too large to pass through said eyes.

8. In combination with a vertically slidable door, a shaft parallel to the upper edge of said door, a counterbalance torsional spring having one end secured to said shaftan arm pivotally mounted adjacent said torsional spring, a nger extending from the remaining end of said spring and engaging said arm under spring tension, a ratchet on said shaft, a pawl pivotally mounted adjacent said ratchet and held by said arm away from said'ratchet, and means tending to throw said pawl into engagement with said ratchet and operative on release of said arm by breaking of said spring.

9. In combination with a vertically slidable door, a shaft parallel to the upper edge of said door, a counterbalance torsional spring having one end secured to said shaft, an arm pivotally mounted adjacent said torsional spring, a stop iinge'r secured to the remaining end of said spring for angular adjustment relatively thereto and engageable with said arm, a ratchet on said shaft, a pawl pivotally mounted adjacent said ratchet and held by said arm away from said ratchet, and

.means tending to throw said pawl into engage-

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