US2929095A - Sash balance - Google Patents

Description

March 22, 1960 w. D. NOBES 2,929,095

' SASH BALANCE Filed May 22, 1957 2 Sheets-Sheet 2 INVENTOR.

W. DOUGL HS NOBES ATTORNEY United States Patent SASH BALANCE William Douglas Nobes, Rochester, N.Y., assignor to The Caldwell Manufacturing Company, Rochester, N.Y., a corporation of New York Application May 22, 1957, Serial No. 660,844 liClaims. (Cl. 16-197) This invention relates to window sash balances of the type in which" a tubular element is fixed to the window jamb or side member, and a twisted flat rod within the tubular element is fixed to a cross-rail of the sash, and

of elements in the ideal structure are such that the action of gravity on the sash is at all times almost exactly offset or compensated for by the torsion created by the balance.

In general, the basic structure of the sash balance according to the present invention is similar to that shown in prior patents such as the patent to Tappan, Number 2,580,705. The outstanding differences are apparent largely because of the material used for certain parts, whereby the necessity of providing lubrication for a multiplicity of component parts is virtually eliminated; thereby resulting in a cleaner article for handling and installation, and obviating the diificul ties attendant in a lubricated device of this nature, such as congealing andstickiug of the lubricant.

Heretofore various types of sash balances have been presented with different means for transforming longitudinal motion into torsional force, or conversely. Each 'of these has been effective to an extent,yet certain objections still arise. One is the noise quite often present in-the use of a rod type balance. This is due to the use of metal against metal in certain sliding parts. Another is the number of parts required for the rod type balance to effectively fulfill its function. Still another is the complexity of certain parts.

It is therefore a prime object of the present invention to overcome the objections to the number and complexity of small parts in a rod type balance by providing for an embodiment having the fewest number possible. This is accomplished by incorporating the functions of a plurality of components into one part. Further contributory to the above is the use of one of a specific group of maerials in the fabrication of the above mentioned part.

A further object of this invention is to overcome the objectionable noise produced when a tubular adapter may stick within the mechanism until the tension of the springs causes the adapter to overcome the sticking or binding and, upon releasing, be propelled by the springs, striking sharply against other parts of the balance. Here again, the use of metal against metal requires a lubricant, which can congeal when cold, or become thin and thereby run when warm.

This tubular adapter, herein called a coupling, in cooperation with a spring, transforms rotational movement into longitudinal force. This is old and is well known to those skilled in the art. Prior concepts have presented various forms of a device to store torsional force. These have all been in varying degrees of complexity, ranging from a single part to many, and have only been efiicient .to limited extents. it is therefore an object of the present invention to simplify and further correlate the assembly of components in a rod type balance for storing torsional force. In this case, the material specified, and when used as described, produces a new and useful effect.

Other objects, features and advantages of the present invention will become apparent and a better understanding of this invention may be had from the following specification when taken in reference to the accompanying drawings in which:

Figure 1 is a fragmentary vertical cross sectional view of a sash balance constructed in accordance with one embodiment of this invention, some portions being omitted as they are known in the prior art.

Figure 2 is a cross sectional view of the invention in part, with some interior details in elevation.

Figure 3 is a section taken on line 33 in Figure 1.

Figure 4 is an elevation of one detail, on a reduced. scale, made of the material to be described in further.

detail.

Figure 5 is a diagrammatic representation of the action: and reaction of the forces of the spring versus the weight. of the sash and gravity.

Figure 6 is a sectional view'on a reduced scale similar to' that taken on line 33 in Figure 1, and showing a.

modification of the present'invention.

-Figure 7is a further modification shown in section: similar to that taken on line 33 of Figure 1.

Figure 8 illustrates on a reduced scale a still further modification of this invention.

Figure 9 is a fragmentary longitudinal cross S$Ctl0l1i on a reduced scale of a sash balance, in part, illustrating. a preferred modification of the invention placed therein- Figure 10 is a longitudinal elevation of the preferred modification of the present invention as illustrated in. Figure 9.

Figure 11 is a top view of the invention taken on line 11.-11 in Figure 10.

Figure 12 is a longitudinal elevation of yet a further modification of the invention on the scale of Figures 9 and 10.

Figure 13 illustrates a longitudinal section of the invention according to the embodiment in Figure 12, along line 13-13 in Figure 14.

Figure 14 is atop view of the invention taken along 5 a line similar to Figure 11.

Referring now to Figure 1, the sash balance has a main structural member'consistingof a tube 10, preferably of metal, the upper end of which is anchored or attached to the inner face of a window frame, commonly designated asthe jamb, by means of a transverse screw or the like. This is not shown as it is known in the art. Within the tube 10 is a helically-formed rod or metal strip 11, the lower end of which may be suitably anchored against rotation by a bracket pinned to it and secured to the bottom rail of a window sash. These elements are known to those skilled in the art .and need no further explanation. n

The tube 10 and the spirally-twisted rod 11 both being held againstrotation, it is apparent that an element slidable on the rod 11 and conforming thereto in section will be rotated as the sash is moved upwardly or downwardly, and this rotational movement is utilized to wind or tension a suitable spring, so that when the sash is raised the unwinding of the spring creates a lift to assist in raising the sash, thus constituting a counterbalance to gravity.

To accomplish the above results, a collar 12, preferably of metal, is supported within the tube 10 on an inwardly-rolled bead 13. Concentric circular bore 14-of this collar 12 amply clears the rod 11. Resting in a counterbore 15 of collar 12 is a sleeve or coupling 16 with a bore 17 that provides a sliding fit for rod, 11. A portion 18 of the coupling 16 has an opening 19 there! through, which, while not a close fit on rod 11, still prevents the coupling 16 from rotating freely on the rod 11.

Referring to Figure 4, the coupling 16 will be seen here as having a short outstanding boss or spring pad 20 and a spring stop 21. Figure 2 illustrates the spring pad 20 and spring stop 21 being used to retain a spring 22 by means of a notch 24 in the end 23 of the spring 22.

A spiral spring 22 is wrapped around the coupling 16 and its upper end is secured, along with the upper end of the tube 10, to the window casing, not shown, so that the spring 22 may be rotated or wound only by a twisting movement of its lower end, thus constituting what is commonly termed a torsion spring. This twisting is accomplished when the sash is moved downwardly because the lower end of the rod 11 is fastened to the sash as aforesaid. Thus the fit of the aperture 19 on the rod 11 causes the coupling 16 to follow thehelices of the rod 11, resulting in a rotation of the coupling 16, as ilwill result, thus shortening the life of the sash balance.

It has been found by the applicant that certain materials can be used in making the coupling 16 which have a low friction and resist wear effectivelyf The following is a partial list of the above mentioned materials:

Nylon Silicone-coated plastics Phenol formaldehyde plastics Vinyl siliconate coated glass fiber materials The undesirable friction and the need for a long-wearing material have both been overcome by the use of the above materials.

The above-mentioned problem of sticking of the coupling, so that the coupling 16 has cause to slam partially the length of the sash balance and produce objectionable noise has been partially overcome by the use of the above described materials, but the problem still partially exists. Figure 8 illustratesamodification of the present invention which overcomes this problem. A modified embodiment of the coupling 16 is shown, with the spring stop 21 removed and the portion 18 of the coupling 16' having the plan view of Figure 7. Referring back to Figure 8, the dotted lines indicated at 18' will show the portion 18' as having a semicircular or ball-bearing shape. This has been found effective in overcoming the sticking, and easing the lateral pressure of the rod 11, thus ultimately reducing wear on the coupling 16. The tube 10" has had its lower end reformed so that instead of the inwardly rolled head 13 completing 180 degrees of circle and returning'as shown in Figure 1 to the plane of the tube, the head 13' presents a flange-like appearance in the modification in Figure 8. The collar 12 has been changed to appear more as a washer-shaped member, and a concentric snap-ring 9 or the like has been fitted to a suitable groove in the lower end of the coupling 16'. This ring ,9 acts 'asa retainer and prevents the coupling 16 from being pushed inside of the tube from which the head is formed.

is the resultant force which the sash balance exerts, tending to lift the sash.

With reference to Figure 1, a portion 16A is shown as being beveled. This beveled portion 16A may extend downwardly along the body of the coupling 16 for substantially a third of its length. This is to aid in preventing binding of the spring 22 as it is being torsioned by the coupling 16 being rotated by the action of rod 11 as the sash, not shown, is moved upwardly or downwardly in the jamb or frame of the window.

Referring now to Figures 9, l0, and 11, a preferred embodiment of the invention is illustrated as having certain modifications including a stepped portion 16A. It has been found inactualpractice that a coupling 16" having its portion 16A in the form of a reduced diameter with respect to the diameter of the body of the coupling 16" performs its function with greater efficiency. As a sash is raised or lowered inits frame, the rod 11 is twisted, thus impartinga rotational motion to the coupling 16". Spring 22' beingi'fastened at its lower end to the coupling 16" is twisted,or .otherw ise torsioned. It is immediately obviousthat any convolution 22A located near the portion 16A of coupling 1 will be moved longitudinally along portion 16A of coupling 16 as this torque is applied to the spring 22'. Thoseskilled-in the art will also readily see that at the momentthis torque is applied, twisting the spring 22, the spring will be wound slightly, reducing its diameter. arms the spring 22' tends to bind with the coupling 16" at portion 16A. With this coupling 16 having its portion 16A reduced in diameter it is obvious that as the torque is imparted to the spring 22', thus twisting the spring and: ultimately reducing itsdiameter slightly, the spring 22' is unable tobind with the portion 16A of coupling lfi". This is very important to the efiic ient operation of the balance, since binding of the spring 22 thus being eliminated, sticking of the balance is thus overcome. This sticking is inherent in balances of this type heretofore presented. In Figure 9, the convolution 22A is shown encircling the body of the coupling 16" and also'part of thefportion 16A thereof. The effect of the reduced diameter portion 16A is apparent in that there is a greater clearance between the inner diameter of the spring 22' and the coupling. The stepped portion 16A of the coupling also performs the function of restricting theiredu ctio n in diameter of the spring, on winding, to a gradual taper from the maximum diameter on portion 16" of the coupling to its minimum diameter along the unsupported length. This gradual tapering of the spring diameter inhibits the tendency of the spring to cock or bend along its axis at a point adjacent to the end of the coupling, and so inhibits .the resultant cocking of the coupling against the housing and the rod which passes through it, with attendant binding and increase in friction. A tapered portion ,at 16A would urge much the same taper and inhibition in the spring, but will also tend to camthe spring coils off the coupling, an undesirable function which could lead to balance failure. The stepped portion 16A eliminates .this camrning.

Figures 10 and 11 further illustrate the modification of the portion 16A of the coupling and illustrate another feature of this preferred embodiment. Spring pad 20' is here illustratedasbeing beveled, with its upper end blended into and with the plane of the body of thecoupling 16 to form guide portion 20" and abutment portion 20. The notch 24 in the end 23' of spring 22', Figure .9, is illustrated as being placed conversely in respect to the location of the notch 24 illustrated in Figure 2. Due to the direction of the forces present as a sash is balanced'by ito-co-operatively perform their functions more efficiently.

The beveled uppenedge, or plane of the guide portion 20" of spring pad 20' allows simpler, more efficient assembly of the'components of the balance. The spring 22', with the notch 24 cut therein, is placed downwardly over the body of the coupling 16 with the notch 24' in alignment with the spring pad 20'. As the end 23 of the spring 22 engages guide portion Zti of the spring pad 20, the end 23 is lifted over the spring pad 29 until the notch 24 passes over the pad 26, the end 23 of spring 22' then snapping into place beneath the abutment portion 20'.

Figures 12, 13, and 14 illustrate a yet further modification of the coupling 16" in that the coupling is reduced in size longitudinally which prevents the aforementioned binding. Further modifications to the spring pad 20"" are seen which simplify assembly of the balance.

It is to be understood that further modifications to this invention may be made from time to time which do not depart from the true spirit and scope of the invention as disclosed in the appended claims.

I claim: 7

1. A sash baiance comprising a tubular member for securement to a jamb, a helically formed rod extending longitudinally in said tubular member for securement to a sash, a torsion spring for securement to the jamb at its upper end and convoluted about said rod within said tubular member; a tubular coupling through which said rod extends and having an apertured portion therethrough substantially conforming in cross-section to said rod, said torsion spring at its lower end being wrapped around said coupling and retained thereto, coupling support means at the lower extremity of said tubular member rotatably supporting said coupling within said tubular member, said coupling being rotated by said rod upon movement of said sash thereby causing twisting of said torsion spring whereby torsional force is stored for counterbalancing the sash, said coupling having an upwardly, longitudinally extending portion of reduced diameter relative to the lower portion of said coupling, said coupling having a laterally extending spring pad providing a lower abutment for retaining said torsion spring, said torsion spring having a notch portion opening upwardly in the lower end thereof, said notch portion engaging beneath said abutment of said spring pad, said spring pad including a guide portion extending outwardly from the coupling downwardly toward said abutment for permitting the lower end of said torsion spring to be guided thereover into engagement with the abutment during assembly, said reduced diameter portion of said coupling preventing binding of said torsion spring with said coupling to prevent said torsion spring from cocking when said torsion spring is torsionally wound around the reduced diameter portion of said coupling when said coupling is rotated by said helically formed rod.

2. A sash balance comprising a tubular member for securement to a jarnb, a helically formed rod extending longitudinally in said tubular member'for securement to a sash, a torsion spring for securement to the jamb at its upper end and convoluted about said rod within said tubular member; a tubular coupling through which said rod extends and having an apertured portion therethrough substantially conforming in cross-section to said rod, said torsion spring at its lower end being wrapped around said coupling and retained thereto, coupling support means atextending portion of reduced diameter relative to the lower portion of said coupling, said coupling having a laterally extending spring pad for retaining said torsion spring, said torsion spring having a notch formed in the lower end thereof, said notch engaging on said spring pad, said reduced diameter portion of said coupling preventing binding of said spring with said coupling by preventing cooking of said spring, said spring being torsionally wound around said coupling when said coupling is rotated by said helically formed rod. I

3. A sash balance comprising a tubular member for securement to a jarnb, a helically formed rod extending longitudinally in said tubular member for securement to a sash, a torsion spring for securement to the jamb at its upper end and convoluted about said rod within said tubular member; a tubular coupling through which said rod extends and having an apertured portion therethrough substantially conforming in cross-section to said rod, said torsion spring at its lower end being wrapped around said coupling and retained thereto, coupling support means at the lower extremity of said tubular member rotatably supporting said coupling within said tube, said coupling being rotated by said rod upon movement of said sash thereby causing twisting of said torsion spring whereby torsional force is stored for counterbalancing the sash, said coupling having an upwardly, longitudinally extending portion of reduced diameter relative to the lower portion of said coupling, said coupling including abutmentand-guide means on a lower portion thereof for retaining said torsion spring thereto, a notch on the lower end of said torsion spring adapted to slide over a guide portion of said abutment-and-guide means and subsequently engage an abutment portion of said abutment-and-guide means during assembly of said torsion spring on said coupling.

References Cited in the file of this patent UNITED STATES PATENTS Decker et a1. Sept. 16, 1958

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