US2792589A - Counterbalancing mechanism - Google Patents

Description

May 21, 1957 w. YOUNG 9 I COUNTERBALANCING MECHANISM Filed Nov. 18, 1954 3 Sheets-Sheet l 1L2 Hazy, dCCeaaewZ g IYZDMZZflE-zecwtz ir,

May 21, 1957 r w. YOU NG 2,792,589

COUNTERBALANCING MECHANISM 3 Shee ts-Sheet 2 Filed Nov. 18. 1954 3 SheetS-Sheet 3 EUcizztaE W. YOU NG COUNTERBALANCING MECHANISM May 21, 1957 I Filed Nov. 18, 1954 Tired States Patent 2,792,589 COUNTERBALANCING MECHANISM Application November 18, 1954, Serial No. 469,765 1 Claim. (Cl. 16-201) William Young, deceased,

This invention has reference to counter-balancing mechanism for vertically sliding windows and particularly to constant balancing mechanism of the type comprising a transverse spindle with helical scroll or thread and which is rotated on the opening and closing of the window, a traveller member mounted thereon and co-operating with the scroll or thread so that it will be moved laterally when the spindle is rotated, and a helical compression spring which acts on the traveller member so that the latter exerts a torque on the spindle, the scroll or thread having a pitch which increases from one end to the other so that the torque transmitted to the spindle remains substantially constant irrespective of the position of the window.

Heretofore, in window balance kind set forth it has mechanism of the been the practice to make the necessary adjustment in the spring before fitting the mechanism to the window. With this procedure however it is difficult to obtain such adjustment which will most efiectively balance the window.

The present invention has therefore for its object to provide an improved mechanism of the kind set forth which can be fitted to a window without adjustment and adjustment thereafter effected in a simple and etfective manner, the adjustment so obtained being such as will most effectively counter-balance the window.

A preferred embodiment of the invention will now be described by way of example with reference to the annexed drawings which show the improved balance mech- 'anism applied to a half-drop window. In the drawings,

Figure 1 is an elevation of a half-drop window with balance mechanism in accordance with the invention;

Figure 2 is a section on the line 2-2 of Figure 1;

Figure 3 is a sectional elevation of the improved counter-balancing mechanism;

Figure 4 shows one end of the improved counterbalancing mechanism;

Figure 5 is a section on the line 5-5 of Figure 4;

Figure 6 is a section on the line 6-6 of Figure 3 and Figure 7 is a section on the line 7-7 of Figure 3.

As shown in the drawings the half-drop window comprises a fixed outer frame a the bottom half of which is glazed with a fixed pane b. Slidable vertically in the fixed frame is a top half glazed frame arranged to move approximately half the depth of the fixed outside frame.

On the middle of the fixed frame a transverse tubular casing d is firmly attached and in this tubular casing is fitted a spindle e having a helical scroll or thread e Moounted on said scroll is a traveller member 1. The cross section of the casing and the traveller member is non-circular as shown in Figure 7 so that when the spindle is rotated the said traveller member f can travel laterally thereon but cannot rotate.

One end of the spindle g which meshes with one of a h]. having an enclosing casing j longitudinally-sliding locking has fast thereon a pinion wheel pair of vertical racks h and with slot in which is fitted a key k, the end k of which secured to the top half glazed frame 0, said wheel ,5 8 9 Patented May 21, 1957 ice . 2 is arranged to engage with the wheel therein by fitting in the gap between adjacent teeth. The other end of the spindle has fitted loosely thereon one member I of a dog clutch. This member is provided with a series of holes I which can be brought into register with an axial slot m in the tubular casing d.

The other member 11 of the dog clutch is integral with or has secured thereto the other pinion wheel 0 which latter is likewise enclosed within a casing p secured to the fixed frame. The pinion wheel 0 meshes with the other rack h The helical scroll or thread is encircled by a helical compression spring q one end of which is anchored to the non-rotatable traveller member 7 and the other to the dog clutch member I, said spring normally holding the clutch members in engagement with each other.

The pitch of the helical scroll or thread is not uniform but increases as it approaches the end carrying the clutch.

When the top half glazed frame 0 is being raised and lowered the two pinion wheels g and 0 will be rotated by meshing with the racks h and h and in consequence the spindle e with scroll or helical thread will likewise be rotated. The traveller member 1 mounted thereon, being incapable of rotation, will travel transversely to the left or to the right as the case may be and in doing so will increase or decrease, according to its direction of movement, both the compression and the torsion of the spring q. The force of the spring acting on the traveller member f imparts a torque to the spindle which tends to rotate the pinion wheels so that they will oppose the downward movement of the window. The torsion of the spring tends to rotate the spindle in the same direction so that the compression and torsion of the spring combine to impart a torque to the spindle tending to oppose the downward movement of the window. The pitch of the helical scroll or thread is so varied that the torque due to the compression and torsion of the spring is substantially uniform so that in all positions of the sliding window the latter is balanced.

In fitting the window it is necessary to regulate the torque imparted by the spring and also it may be necessary to subsequently adjust said torque.

Assume it is desired to impart to or increase the torque in the spring.

The window is first moved to its lower position. This imparts more turns to the spring and increases the torque therein. Thereafter by means of a suitable tool, such as a rod r shown in Figure 3, inserted through the slot m and a hole I in the clutch member I, the clutch members can be disengaged. While still holding the clutch members disengaged the window is raised, the increased torque being maintained and thereafter the clutch members are permitted to engage. Thus an increased torque is imparted to the spring. To further increase the torque the foregoing cycle of operations is repeated as often as may be required.

Should the torque of the spring be too great the window is first raised, thereby decreasing the torque. Thereafter the clutch members are disengaged and while holding them in such position the window is lowered. When the window is lowered the clutch members are permitted again to engage, the spring then being at the decreased torque. Such cycle of operations may be repeated as desired.

To lock the window the key k is pushed through the casing to fit between adjacent teeth of the pinion wheel g located therein.

If desired the spindle may be rotated by means of a suitable hand lever or power means and gearing to raise and lower the window.

What is claimed is:

In a vertically sliding window, balance mechanism therefore comprising a transverse spindle with helical scroll having a pitch which decreases from one end to the other, means whereby said spindle is rotated by raising and lowering the window, a traveller member mounted on the spindle and co-operating with the scroll so that it will be moved laterally when the spindle is rotated, a helical combined compression and torsion spring encircling the spindle and anchored at one of its ends to the traveller member, a first clutch member fast on the spindle and a second clutch member to which the other end of the spring is anchored and which is held normally in driving engagement with the first clutch member by means of said spring, the second clutch member being capable of axial displacement to disengage the clutch members by manual means and, when so displaced and held against rotation, the tension of the spring can be altered by raismg or lowering the window to rotate the spindle and the spring held in the tension to which it is altered by permitting the clutch members to re-engage.

References Cited in the file of this patent UNITED STATES PATENTS

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