US2630596A - Window sash balance - Google Patents

Description

March 10, 1953 G. STEINGRUBER WINDOW SASH BALANCE 3 Sheets-Sheet 1 Filed Aug. 17, 1948 INVENTOR.

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3 Sheets-Sheet 2 G. STEINGRUBER WINDOW SASH BALANCE 1N.VENTOR.

March 10, 1953 Filed Aug.

- 0 m @N Nu? N 0 0 AW March 10, 1953 Filed Aug. 17, 1948 G. STEINGRUBER WINDOW SASH BALANCE 3 Sheets-Sheet 5 NTOR.

Patented Mar. 10, 1953 WINDOW SASH BALANCE George Steingruber, Atlanta, Ga. Minnie Baas Steingruber, executrix of said George Stein gruber, deceased Application August 17, 1948, Serial No. 44,679

11 Claims. (01. 16-198) The present invention relates to balancing means for sliding window sashes and the like, and more particularly, to an improved window sash balance of the spring-operated type.

While spring-operated window sash balances are not new, generally speaking, they have never been extensively adopted or received general approval of the public or the building trade. This lack of commercial success has been largely due to the numerous practical disadvantages and defects inherent in all the balancing devices of this type which have heretofore been proposed, and especially due to the tendency of frequent breakage of the springs.

I have found that in the use of coil springs which are wound up sufficiently tight to create a torque of such magnitude as to be capable of balancing the weight of a window sash, the frequent winding and unwinding of the spring incident to raising and lowering of the sash, soon causes the spring to break if the spring is anchored in a fixed position at its opposite ends, as is the common practice. In addition, such springs tend to buckle and assume a wavy form longitudinally of the coil, when wound tightly, with consequent loss of power, increased frictional contact with adjacent parts or surfaces,

and other impairments.

It is the primary object of the present invention to provide a simple and effective window sash balance which eliminates the difficulties and'defects just referred to, and which may be applied to single or double-hung window sashes of practically any type of window construction, whether of wood or of metal, and irrespective of the size and/or weight of the sash.

According to this invention, my sash balance comprises a rotatable shaft about which is wound a coil spring of appropriate size and length, commensurate with the weight of the sash which is to be balanced thereby, one end of said spring being anchored to the shaft for rotation therewith incident to raising and lowering of the sash,

and the other end of the spring being connected to a movable anchor which is free to move axially relative to the spring responsive to winding and unwinding thereof.

A further object of the invention is to provide an improved sash balance mechanism which may be quickly and easily attached to or detached from window sashes through means of thin, flexible cables or bands of stainless steel or the like, which occupy little space and are inconspicuous when installed, yet possessed of great strength.

A still further object of the invention is to provide a sash balance mechanism which includes means for locking and releasing a spring-controlled balance shaft, at will, whereby to facilitate initial winding or adjustment of the spring preliminary to installation of the balance mechanism in a window structure, or to preserve and maintain the parts of the mechanism in a condition of rest during removal of the mechanism for purposes of adjustment or repair.

Other and further objects and advantages of the invention will be hereinafter described and the novel features thereof defined in the appended claims.

In the drawings: 7,

. Figure l is a view partly in horizontal section and partly in top plan, of a metal window structure of the .double-hungvertically sliding sash type, showing a typical application of my improved spring-operated sash balance;

Figure 2 is a fragmentary vertical sectional view as taken on the line 2-2 of Figure 1, with one of the sashes and certain parts of the sash balance mechanism shown in elevation;

Figure 3 is a vertical sectional view through the complete window structure as taken on the line 3-3 ofFigure 2, transversely to the plane of the window, and more particularly showing the balanced suspension of both sashes by the respective separate spring-operated sash balancing mechanisms located at the top of the Window frame and connected to the sashes by flexible, thin stainless steel bands or cables wound about drums on the spring-controlled balance shafts, with the free ends of the bands anchored to the upper edges of the respective sashes;

view taken on the line 66 of Figure 2, and showing the balance shaft looks or clamps;

Figure 7 is an enlarged vertical sectional view through one of the cable or band drums on one of the balance shafts, and particularly showing the manner of connecting the inner end of the band to the drum;

Figure 8 is a fragmentary vertical sectional view as taken on the line 88 of Figure 1;

Figure 9 is an enlarged perspective view of one of the balance shaft guides or supports; and

Figure is a fragmentary perspective View of the base plate or frame of the sash balance mechanism.

Like reference characters designate corresponding parts in the several figures of the drawings, wherein my improved window sash balance mechanism i shown in a form which is more particularly suitable for application to metal win dow structures of the double-hung, vertically sliding sash type. It is to be understood, however, that the balance mechanism is not limited to use with the specific type of window construction illustrated in the drawings, but is equally applicable to window structure of wood, or partly of ,wood and partly of metal, as well as to other all-metal structures.

According to the construction as illustrated in the drawings, it will be seen that the window structure generally conforms to that dis-closed in my co-pending application Serial No. 768,179, filed August 12th, 1947, now abandoned. These structures are characterized by the utilization of metal' extrusions of aluminum or the like which are assembled together to provide a generally rectangular frame designated I, of appropriate size, the frame including a sill 2 extending transversely across the bottom thereof, and a pair of upright members of generally channel-form which are rigidly attached at their lower ends to the respective opposite ends of the sill 2, the upright members being designated 3, 3 and forming the sides of the window frame. The attachment of the members 3, 3 to the sill 2 may be made. in any suitable manner, but preferably by means of an anchor bolt 4 extending upwardly through the sill 2 near the end thereof, and terminating at its upper end in a hook 5 which engages in an opening 6 formed in the upright. By. tightening the nut l on the threaded lower end 8 of the anchor bolt 4, the upright 3 will be firmly and rigidly anchored to the sill, as more particularly described and illustrated in my 00- pending application above referred to.

Similarly attached by corresponding anchor bolts 4 to the upper end of the uprights 3, 3 is a base plate generally designated 9, said base plate forming a supporting frame for the sash balance mechanism hereinafter described, as well as forming the head of the window frame, said base plate 9 extending transversely across the upper end of the members 3, 3, as shown in Figure 2.

Suitably attached at the center of the inner face of each upright 3, as by means of screw fastenings I0, is a parting strip II, said parting strips extending vertically at each side of the window frame from the sill 2 to the base plate 9 at the upper end of the window frame. These parting strips may also have the form of extruded channels of aluminum or other metal and coact with stop strips I2 at the front and back 'faces of the window frame to form guideways or channels in which the window sashes, generable in the usual manner of a double-hung window. A corresponding parting strip I5 extends transversely across the lower face of the base plate 9 at the upper end of the window frame, in th plane of the parting strips II, II, this parting strip I5 being either formed as an integral part of the base plate 9, as shown in the drawings, or formed separately and attached to the base plate, whichever is preferred.

The sashes l3 and I4 may be of any desired construction, but preferably are of the type as disclosed in my co-pending application hereinbefore referred to, the sash I3 being the lower sash, and the sash I4 being the upper sash when the window is closed. The bottom edge of the sash l3 and the top edge of the sash I4 are each preferably provided with a resilient sealing member I5 such as a rubber or other sealing strip which is seated in a flanged mounting plate I6 suitably attached to the edge of the sash, as by means of screw fastenings l1. Attached by screw fastenings I8 to the upper edge of the sash I3 is a plate I9 which overhangs the face of the sash next to the sash I4, as best shown in Figure 3, the overhanging edge of the plate l9 forming a meeting rail and terminating in a downwardly bent flange 20 which engages a rubber or other sealing strip 2| mounted in a channel 22 extended across the adjacent face of the sash I4 near the lower nd of the latter, such engagement being effected when the sashes are closed, to prevent air and the elements of the weather from entering between the sashes. As shown in Figure 2, a pivoted cam lock 23 is provided to permit the sashes to be locked in their closed positions, when desired, such lock serving to force the sealing strips l5 tightly against the window frame, and the flanged edge 20 of the meeting rail I8 tightly against the sealing strip 2!, when the cam lock 23 is manipulated to its locking position in the conventional manner.

It will be seen from the drawings that the upper side of the base plate 9 at the upper end of the window frame has a pair of spring-controlled balance shafts designated 24 and 25 rotatably mounted thereon, there being one of said shafts for each of the respective window sashes I3 and I4. Each shaft is journaled in a plurality of brackets generally designated at 26, there preferably being four such brackets for each shaft, a best shown in Figures 1 and 2. The brackets may all be identical with each other and preferably have the form of a U- shaped member which includes a flat plate 21 at the bottom thereof, the opposite ends of the plate being bent upwardly so as to provide two spaced end walls 28, 28, each having an opening 23 therethrough for receiving the balance shaft. In order to mount the brackets 23 on the base plate 9, the upper side of th base plate is provided with two sets of flanges respectively designated 30 and 3!, the flanges being parallel to each other and extending length-wise of the plate 9 from end-to-end thereof. As will be best seen from Figure 10, the free edges of each set of flanges are turned inwardly in opposed relation to each other and are spaced above the upper surface of the plate 9, thereby forming two ways respectively designated 32 and 33 running parallel to each other across the plate from end-toend. The brackets 26 may thus be assembled on the plate 9 by sliding the same into the ways 32 and 33 from either end thereof, and when so assembled, the bottom plate; 21; ofeach bracket seats fiat against the upper surface of the plate swith the opposite marginal edges of the bottom plate disposed beneath the inwardly turned flanges 33 or 3i, as th case may be, so as to prevent the brackets 26 from rocking, twisting or otherwise moving out of alignment in the respective ways 32 and 33. The opposite edges of each end wall 28 of each bracket are notched, as at 34, 34, as best shown in Figure 9, to slidably receive the inwardly turned flanges 33 or 3| and thus permit assembly of the brackets 26 in the respective ways of the plate 9.

When the brackets 26 have been assembled in the ways 32 and 33 in the manner above described, they are arranged in spaced relation to each other as shown in Figures 1 and 2 of the drawings. One of the brackets is disposed adjacent to each end of the balance shaft 24, and a corresponding bracket is disposed adjacent to each end of the balance shaft 25, all of these end brackets being suitably anchored to the plate 9 so as to always remain in a fixed position. For

convenience and simplicity of manufacture, an-

chorage of these end brackets may be accomplished by providing the opposite edges of thebottom plate 2'! of each bracket with a notch or recess 35, and after the brackets have been located in the proper positions in the respective ways 32 and 33, the flanges 3B and 3| are depressed or deformed as by means of a punch or other suitable tool, into the respective notches 35, thereby positively interlocking the brackets 26 with the plate 3 to preclude any displacement of th brackets endwise in the ways. Thereafter, if it is desired to release the brackets 26 to permit their removal from the plate 9 for purposes of replacement or repair of the sash balance mechanism, it is only necessary to force upwardly the depressed portions of the flanges 30 and 3! so as to free the same from the notches 35. This operation can be accomplished by means of a screwdriver or other pointed tool.

Between the end brackets of the respective balance shafts, and located substantially midway of each balance shaft but in spaced relation to each other are two other brackets 26, one of which is anchored to the plate 9, as by depressing the flanges 36 and 3| into the notches 35 of the respective bottom plates 21, as indicated at 36 in Figures 1 and 6, while the other bracket is left free to slide in its way. Between these two intermediate brackets and encircling the central portion of each balanc shaft is a coil spring 31,

I there being one coil spring for each balance shaft,

and the opposite ends of the respective coil springs abutting against the opposing end walls 28 of the respective intermediate brackets 26. By this arrangement, the coil springs 3'! always tend to urge the freely movabl intermediate bracket 26 away from the fixed r anchored intermediate bracket. At the opposite side of the intermediate freely movable bracket on each balance shaft, 2, second coil spring 36 is loosely mounted on the balance shaft. One end of this coil spring is anchored to the adjacent end wall 26 of the freely movable intermediate bracket 26, as by hooking the end of the spring through two small apertures 36 formed in this bracket, while the opposite end of the coil spring 33 is passed diametrically through a sleeve 40 and through the balance shaft which is provided with a diametrical opening 41 therethrough, as best shown in Figure 8. The sleeve 43 is disposed on the balance shaft adjacent to the fixed end bracket 26 at the cor responding end of the spring 38, and the sleeve 46 tends 'to hold the spring'38 in concentrically 75 turns as are necessary to permit vertical move- 6 spaced relation to the balance shaft, thereby minimizing friction or drag of the spring on the shaft.

It will be understood from the foregoing that the spring 38 on each balance shaft is anchored at one end to the shaft and at the other end to the freely movable intermediate bracket 26. Accordingly, by rotating the balance shaft, the spring 38 will be wound or unwound, depending on the direction of rotation of the balance shaft, while the freely movable bracket 26 is caused to slide on the balance shaft so as to always urge the coils of the spring 28 closely together as the length of the spring shortens during unwinding and lengthens during winding thereof. It is this arrangement of the spring 38 and the movable intermediate bracket 26 which is yieldingly urged toward the spring 38 by the spring 31, which prevents breaking of the spring 38 such as would occur if the movable intermediate bracket 26 were anchored in a fixed position. In addition, the arrangement as above described always maintains the coils of the spring 38 close together and in axial alignment with each other, thereby avoiding any tendency of this spring to become distorted or deflected to one side or the other, as commonly referred to as caterpillaring. The elimination of such distortion of the spring prevents any tendency of the spring to impart a frictional drag to the balance shaft, as well as reduction of the stored power or torque of the spring by contact with the surrounding parts of the frame or other mechanism.

In order to transmit the balancing force of the springs 38 and balance shafts 24 and 25 to the window sashes l3 and I4, it will be observed from the drawings that each balance shaft is provided at its opposite ends with a flanged pulley or drum 42. Each end of each balance shaft is slotted as at 43, with the slot extending inwardly from the end of the shaft to the inner side of the drum or pulley 42. The central portion of each drum 42, that is, the portion lying between the flanges 44, is also slotted so that when this slot, designated 45, is registered, with the slot 43 in the shaft, the free end of a band or cable 46 can be inserted through both slots 45 and 43, as shown in Figures '7 and 8, for the purpose of anchoring the free end of the cable or band 46 to the balance shaft on which the drum or pulley 42 is mounted. At the same time, the inserted end of the band or cable 46, which preferably hasthe form of a relatively thin, flexible, stainless steel band, serves to key the pulley 42 to the balance shaft, without the aid of any spe cial key or other fastening instrumentalities. Due to the thinness of the stainless steel band 46, it is desirable to double the end of the band, as clearly shown in Figure 7, before inserting the same through the slots 45 and 43, thereby strengthening the connection between the band and the balance shaft, as well as between the pulley and the balance shaft. Due to the absence of any screws or other connecting instrumentalities passing through the flexible band, break age of the band at the anchored end thereof is minimized, and at the same time, the band can be quickly connected and disconnected at will, as well as the pulley or drum, in case it is necessary or desirable to remove the band and the pulley or drum from the balance shaft for purposes of adjustment or repair of any parts of the balance mechanism.

Each band or cable 46 is wrapped around the pulley or drum 42 for a sufficient number of ment of the respective window sashes in the window frame to which, the opposite. ends of the cables or bands 46 are connected or anchored as shown in FiguresZ and 3 of the drawings. The latter connections. are also preferably made without any screws or fastenings penetrating the bands or cables, as by suitably slotting the opposite ends of theupper faces of the respective window sashes l3. and Hi to receive the bands. therein in the manner of a looped anchor, as more particularly shown in Figure 3 of the drawings'. It is to be understood, however, that the details of these anchor connections are not material to the, present invention, since any suitable type of anchoragemay be employed to anchor the ends of therespective cables or hands 46 to the window sashes. Due to the thinness of the bands orcables, they occupy little space and are inconspicuous, yet possessed of ample strength to support the weight, of the window sashes of practically any type or construction, whether of wood or of metal, which would ordinarily be required practice. If desired, the parting strips l I may be recessed slightly at their opposite. f c s. a n i a ed at H in Figure 2, so that t e able or ban s 46. W i in the recesses which will aid in holding the bands in alignment with the drums or pulleys on which they are wound, as the sashes are raised and lowered in the window frame.

Itwill be obvious that before the cables or bands. 46 are, connected to the window sashes l3 and I4, it is necessary to. wind the springs 38 Q11: the respective balance shafts 24 and 25 to an extent sufficient to support. the weight of the window sashes. In their wound condition, the springs, 38 are foreshortened and the indiidual coils thereof will closeup when the spring is fully woundso that the individual coils of each spring abut. against each other. In order to hold the springs in a. wound condition. while the cables; or hands 46 are connected to the drums orpulleys 42 and to the window sashes, brake meansor clamps are. provided for the respective balance.- shafts 24 and 25', as indicated at. 4"! in Figures 1' and 6. Each brake means or clamp 4! has the form of a strap or band of metal which extends about the balance shaft and is anchored at one end in any suitable manner to the-upper face of the bottom plate 21 of one-of the end brackets 26', as indicated at 43. The opposite end of the band or strap is provided with a threaded aperture to receive an adjusting screw 49 which is threadedly engaged with the aperture and loosely extends through the plate 9'and the bottom plate 2-! of the end bracket 26, with the head of the screw 49 accessible at the top of the window frame when the window sashes are pulled down to permit the screws to be engaged by a screwdriver. The end of the strap or band which is threadedlyengaged with the screw 49 terminates somewhat above the bottom plate 21 of the bracket 26 so that by tightening the screw 49, the stra or band will grip or clamp about the balance shaft and hold it stationary until the balance mechanism has been connected by the cables or bands 46 to the window sash, after which the, screws 49 must be loosened to permit the balance shafts 24 and r 2,5 to, turn freely as the. respective window sashes i3 and M are raised and lowered. When wound, the springs 38 will exertv a suflicient torque upon the balance shafts to balancev the window sashes in any position to, which they are moved within the limits. of, their vertical adjustments in the window fr me, while offering no app eciable resistance to either upward or downward movement of the sashes.

When the balance mechanism is incorporated in a metal window structure so as to form a part of the window frame, as shown by way of illustration in the drawings, a cover or housing 50 is mounted on the plate 9 so as to enclose the respective balance mechanisms as best shown in Figures 3, 4 and 6, said cover being suitably attached to the plate 9, as by means of the anchor bolts 8 which extend through the central depressed portion of the cover, as indicated at 5!, in which the upper ends of the bolts 8 and nuts I lie and terminate below the upper edge of the cover, thereby eliminating any projections which would interfere with the hanging or mounting of the. window in an opening of a building struc ture.

If the balance mechanism is to be applied to an existing window structure, either of wood or of metal, as a separate attachment, therefor, it will be obvious that the plate 9 may be modified by the provision of upwardly extended flanges along its opposite edges to form a channel-like housing which is open at its upper side, and which may be screwed or otherwise secured against the head of the window frame.

Other changes and alterations may be made without departing from the spirit of the invention as defined in the appended claims.

I claim:

1. A window sash balance mechanism of the class described for window structures in which a window sash is vertically slidable in a window frame, comprising a spring-controlled balance shaft rotatablymounted at the top of the win,- dow frame and transversely extended thereacross above the window sash, means for suspending the window sash from the balance shaft, with the window sash balanced by the spring-controlled balance shaft, and means frictionally engageable with. said balance shaft and operable and releasable at will for restraining said bal'ancershaft against rotationl 2., A. spring-controlled balance mechanism, comprising av balance shaft rotatably mounted on a base and having means for connecting the shaft to arr-object to be balanced, a torque spring of helically-coiled form encircling said: shaft, and hayin on end of th p n connected to said shaft, a pressure plate. slidably mounted on, said base andabutting the opposite end of said spring, with the latter end of said spring connected to said pressure plate, and means acting on; said pressure plate for yieldablyurging the same in a direction tending to. maintain the, coils of the torque spring relatively close to. each other at all times during winding and unwinding ofthe torque spring according to the direction of rotation of the balance shaft 3. A spring-controlled balance; mechanism, comprising a balance shaft rotatably mounted on a base and having means for connecting the shaft to an object to be balanced, a torque spring of helically coiled form encircling said shaft. and having,- one end of the. spring connected to said shaft, a pressure plate slidably mounted on said baseand abutting the opposite end of said spring, with the latter end of said spring connected to said pressure plate, and means acting on said pressure plate for yieldably urging the same in a direction tending to maintain. the coils of the torque spring relatively close to each other at all times. during, winding and unwinding, of the torque spring according to the direction of rotation of the balance shaft, said last-named means comprising a second spring of helically coiled form encircling said balance shaft, said second spring being normally compressed and having one of its ends engaging the pressure plate at the side opposite to the torque spring aforesaid, and the opposite end of the second spring engaging a stationary abutment on said base.

4. A window sash balance mechanism of the class described for window structures in which a window sash is vertically slidable in a window frame, comprising a supporting base member adapted to be mounted at the top of said window frame and transversely extended thereacross, a balance shaft rotatably mounted on said base member and transversely extended thereacross above the window sash, a pair of flexible cables fixed to the respective opposite ends of the balance shaft so as to be wound thereon and unwound therefrom upon rotation of the balance shaft in opposite directions, said cables being connected at their opposite ends to the window sash, a coil spring encircling the balance shaft and having one of its ends fixed to the balance shaft, said coil spring being wound to an extent which is sufficient to exert a torque upon the balance shaft capable of balancing the window sash and sustaining the window sash in any position to which it is slidably moved in the window frame, and an anchor member slidably mounted on said base member aforementioned at the opposite end of the coil spring aforesaid and connected to the latter end of the spring, said anchor member being freely movable towards and away from the first-mentioned end of the spring which is connected to the balance shaft, responsive to winding and unwinding of the spring incident to vertically sliding movements of the window sash, said flexible cables having the form of thin, stainless steel bands, drums fixed to the respective opposite ends of the balance shaft and on which the respective bands are adapted to be wound and unwound, each end of said shaft and its corresponding drum being axially slotted to receive an end of one of the hands when the shaft slots and the drum slots are registered with each other, whereby to anchor the ends of the bands to the balance shaft and to the drums, and to simultaneously key the a window sash is vertically slidable in a window frame, comprising a supporting base member adapted to be mounted at the top of said window frame and transversely extended thereacross, a balance shaft rotatably mounted on said base member and transversely extended thereacross above the window sash, a pair of flexible cables fixed to the respective opposite ends of the balance shaft so as to be wound thereon and unwound therefrom upon rotation of the balance shaft in opposite directions, said cables being connected at their opposite ends to the window sash, a, coil spring encircling the balance shaft and having one of its ends fixed to the balance shaft, said coil spring being wound to an extent which is sufficient to exert a torque upon the balance shaft capable of balancing the window sash and sustaining the window sash in any position to which it is slidably moved in the window frame, and an anchor member slidably mounted on said base member aforementioned at the opposite end of the coil spring aforesaid and connected to the latter end of the spring, said anchor member being freely movable towards and away from the first-mentioned end of the spring which is connected to the balance shaft, responsive to winding and unwinding of the spring incident to vertically sliding move-- ments of the window sash, said slidable spring anchor member having the form of a pressure plate and being yieldingly urged against the end of the coil spring which is connected thereto so as to constantly maintain the coils of the coil spring in close relation to each other as the coil spring shortens and lenthens during winding and unwinding thereof by the vertical sliding movements of the window sash and consequent rotation of the balance shaft.

6. A window sash balance mechanism of the class described for window structures in which a window sash is vertically slidable in a window frame, comprising a supporting base member adapted to be mounted at the top of said window frame and transversely extended thereacross, a balance shaft rotatably mounted on said base member and transversely extended thereacross above the window sash, a pair of flexible cables fixed to the respective opposite ends of the balance shaft so as to be wound thereon and unwound therefrom upon rotation of the balance shaft in opposite directions, said cables being connected at their opposite ends to the window sash, a coil spring encircling the balance shaft and having one of its ends fixed to the balance shaft, said coil spring being wound to an extent which is sufficient to exert a torque upon the, balance shaft capable of balancing the window sash and sustaining the window sash in any position to which it is slidably moved in the window frame, and an anchor member slidably mounted on said base member aforementioned at the opposite end of the coil spring aforesaid and connected to the latter end of the spring, said anchor member being freely movable towards and away from the first-mentioned end of the spring which is connected to the balance shaft, responsive to winding and unwinding of the spring incident to vertically sliding movements of the window sash, said slidable spring anchor member having the form of a pressure plate and being yieldingly urged by a separate axially compressed coil spring encircling the balance shaft at the side of the pressure plate opposite'to the first-mentioned coil spring, against the end of the coil spring which is connected thereto so as to constantly maintain the coils of the first coil springs in close relation to each other as the spring shortens and lengthens during winding and unwinding thereof by the vertical sliding movements of the window sash and consequent rotation of the balance shaft.

'7. A window sash balance mechanism of the class described for window structures in which a window sash is vertically slidable in a window frame, comprising a supporting base member adapted to be mounted at the top of said window frame and transversely extended thereacross, a balance shaft rotatably mounted on said base member and transversely extended thereacross above the window sash, a pair of flexible cables fixed to the respective opposite ends of thebal ance shaft so as to be wound thereon and unwound therefrom upon rotation of the balance shaft in opposite directions, said cables being con nected at their opposite ends to the window sash, a coil spring encircling the balance shaft and having one of its ends fixed to the balance shaft,

said coilspring being wound to an extent which is sufiicient to exert a torque upon the balance shaftcapable of balancing the window sash and sustaining the window sash in any position to which it is slidably moved in the window frame, and an anchor member slidably mounted on said base member aforementioned at the opposite end of the coil spring aforesaid and connected to the latter end of the spring, said anchor member beingfreely movable towards and awayfrom the first-mentioned end of the spring which is connected" to the balance shaft, responsive to winding and unwinding of the spring incident to vertically sliding movements of the window sash, said balance shaft being journaled in a plurality of brackets which are assembled on the base member, said base member having a transversely extended way running across the head of the window frame, with the brackets slidable in said way from either end thereof to position the brackets in positions to support the balance shaft at its opposite ends and at an intermediate point of the balance shaft. 1

V 8. A. window sash balance mechanism of the class described for window structures in which a windowsash is vertically slidable in a window frame, comprising a supporting base member adapted to be mounted at the top of said window frame and transversely extended thereacross, a balance shaft rotatably mounted on said base member and transversely extended thereacross above the window sash, a pair of flexible cables fixed to the respective opposite ends of the balance shaft so as to be wound thereon and unwound therefrom upon rotation of the balance shaft in opposite directions, said cables bein connected at their opposite ends to the window sash, a coil spring encircling the balance shaft and having one of its ends fixed to the balance shaft, said coil spring being wound to an extent which is sufficient to exert a torque upon the balance shaft capable of balancing the window sash and sustaining the window sash in any position to which it. is slidably moved in the window frame, and an anchor member slidably mounted on said base member. aforementioned at the opposite end of the coil spring aforesaid and connected to the latter end of the spring, said anchor member being freely movable towards and away from the first-mentioned end of the spring which is connected to the balance shaft, responsive to winding and unwinding of the spring incident to vertically sliding movements of the window sash, said balance shaft being journaled in a plurality of brackets which are assembled on the base memher, said base member having a transversely extended way running across the head of the win-v dow frame, with the brackets slidable in said way from either end thereof to position the brackets in positions to support the balance shaft at its opposite ends and at an intermediate point of the balance shaft, each of said brackets having a notch in at least one edge thereof to permit anchorage of the brackets in their fixed positions on the base by deforming the base at the notches to depress the same into interlocking relation with the notches.

9; A window sash balance mechanism of the class described for window structures in which a window sash is vertically slidable in a window frame, comprising a supporting base member adapted to be mounted at the top of said window frame and transversely extended thereacross, a balance shaft rotatably mounted on said base member and transversely extended thereacross above the Window sash, a pair of flexible cables fixed to the respective opposite ends of the balance shaft so as to be wound thereon and unwound therefrom upon rotation of the balance shaft in opposite directions, said cables being connected at their opposite ends to the window sash, a coil spring encircling the balance shaft and having one of its ends fixed to the balance shaft, said coil spring being wound to an extent which is sufficient to exert a torque upon the balance shaft capable of balancing the window sash and sustaining the window sash in any position to which it is slidably moved inthe window frame, and an anchor member slidably mounted on said base member aforementioned at the opposite end of the coil spring aforesaid and connected to the latter end of the spring, said anchor member being freely movable towards and away from the first-mentioned end of the spring which is connected to the balance shaft, responsive to winding and unwindingof the spring incident to vertically sliding movements of the window sash, said balance shaft being journaled in a plurality of brackets which are assembled on the base member, said base member having a transversely extended way running across the head of the window frame, with the brackets slidable in said way from either end thereof to position the brackets in positions to support the balance shaft at its opposite ends and at an intermediate point of the balance shaft, and the slidable anchor for the coil spring having a form corresponding to the brackets aforesaid, with the balance shaft journaled therein and being freely slidable on the balance shaft in spaced relation to the intermediate bracket.

10. A window sash balance mechanism of the class described for window structures in which a window sash is vertically slidable in a window frame, comprising a supporting base member adapted to be mounted at the top of said window frame and transversely extended thereacross, a balance shaft rotatably mounted on said base member and transversely extended thereacross above the window sash, a pair of flexible cables fixed to the respective opposite ends of the balance shaft so as to be Wound thereon and unwound therefrom upon rotation of the balance shaft in opposite directions, said cables being connected at their opposite ends to the window sash, a coil spring encircling the balance shaft and having one of its ends fixed to the balance shaft, said coil spring being wound to an extent which is sufilcient to exert a torque upon the balance shaft capable of balancing the window sash and sustaining the window sash in any position to which it is slidably moved in the window frame, and an anchor member slidably mounted on said base member aforementioned at the opposite end of the coil spring aforesaid and connected to the latter end of the spring, said anchor member being freely movable towards and away from the first-mentioned end of the spring which is connected to the balance shaft, responsive to windmg and unwinding of the spring incident to vertically sliding movements of the Window sash, said balance shaft being journaled in a plurality of brackets which are assembled on the base member, said base member having a transversely extended way running across the head of the wind-ow frame, with the brackets slidable in said way from either end thereof to position the brackets in positions to support the balance shaft at its opposite ends and at an intermediate point of the balance shaft, and the slidable anchor for the coil spring having a form corresponding to the brackets aforesaid, with the balance shaft journaled therein and being freely slidable on the balance shaft in spaced relation to the intermediate bracket, and a second coil spring encircling the balance shaft and interposed between the intermediate bracket and the slidable anchor bracket aforesaid for yieldably urging the slida-ble anchor bracket against the adjacent end of the first-mentioned coil spring.

11. A window sash balance mechanism of the class described for window structures in which a window sash is vertically slidable in a window frame, comprising a supporting base member adapted to be mounted at the top of said window frame and transversely extended thereacross, a balance shaft rotatably mounted on said base member and transversely extended thereacross above the window sash, a pair of flexible cables fixed to the respective opposite ends of the balance shaft so as to be wound thereon and un-,

wound therefrom upon rotation of the balance shaft in opposite directions, said cables being connected at'their opposite ends to the window sash, a coil spring encircling the balance shaft {and having one of its ends fixed to the balance shaft,"

said coil spring being wound to an extent which is suflicient to exert a torque upon the balance shaft capable of balancing the window sash and sustaining the window sash in any position to which it is slidably moved in the window frame, and an anchor member slidably mounted on said base member aforementioned at the opposite end of the coil spring aforesaid and connected to the latter end of the spring, said anchor member being freely movable towards and away from the first-mentioned end of the spring which is connected to the balance shaft, responsive to winding and. unwinding of the spring incident to vertically sliding movements of the window sash, said balance shaft being provided with releasable clamping means operable at will for holding the balance shaft against rotation under the influence of the torque of the coil spring, said clamping means having the form of a band embracing the balance shaft and operable by a screw accessible from the inner face of the window frame to tighten and loosen the band about the balance shaft to respectively clamp or release the shaft.

GEORGE STEINGRUEER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 758 Kimballe May 30', 1838 329,409 Ormsby Oct. 27, 1885 416,207 Bastian Dec. 3, 1889 866,278 Hemenway Sept. 17, 1907 2,112,650 Girard Mar. 29, 1938 2,190,098 Dautrick Feb. 13, 1940 2,314,015 Parsons Mar. 16, 1943

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