Improvements in and relating to Appliances for Balancing and Fastening Window Sashes.
Year: 1894

page_text: Date of Application, 6th Feb., 1894
Complete Specification-Left, 6th Nov., 1894-Accepted, 29th Dec., 1894
PROVISIONAL SPECIFICATION.
[Communicated from abroad by DANIEL BATES GILLETTE, Jr., Mining
Engineer, and JOHN DE WITT HAMILTON ALLEN, Gentleman, both of
Pacific Union Club, San Francisco, California, United States of America.]
Improvements in and relating to Appliances for Balancing and
Fastening Window Sashes.
:
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby declare
the nature of this invention to be as follows:-
This invention relates to means for balancing the weight of window sashes so
that they will run easily in the sash frames and also for fastening the sashes at any
desired height in the sash frames, the object being to produce a more convenient
and efficient, and at the same time less expensive balance than those now in
general use.
The invention is embodied in a construction in which the weight of the sash is
counterbalanced by the force of a single spring which force is applied to and
divided equally between the two sides of the sash.
The sash balancing mechanism of the present invention comprises a rod or shaft,
preferably above the top member or head of the sash frame (although it may if
desired be placed below the sill) said shaft having fixed to its ends the winding
reels or pullies, preferably located just over the ends of the sash, to which reels are
connected suspending bands which extend down through openings in the head of
the sash frame and are connected with the side members or stiles of the sash. A
long spiral spring, preferably containing two or more layers of coils, encircles the
said shaft and has one end connected therewith and the other made fast to the
stationary structure so that the force of the spring is applied to rotate the shaft in
the direction to wind the suspending bands thereon and thus having a tendency to
raise the sash, which tendency is substantially sufficient to balance the weight of
the sash leaving it free to move under any extraneous force sufficient to overcome
inertia and friction.
With the mechanism thus far described it is impossible to exactly counterbalance
the weight of the sash in all positions, for, if the spring be of sufficient tension to
hold the sash in its highest position, the winding up of the spring by the lowering
of the sash will so increase the tension of the spring that it will overbalance the
weight of the sash and thus tend to cause the sash to rise, while, on the other
hand, if the spring just balances the sash in its lowest position, it will become
weaker, by unwinding, as the sash is raised and thus will not have quite enough
tension to fully balance the sash in its highest position, so that the latter will tend
to descend by the force of gravity.
These objections are largely overcome by employing a multiple layer spiral
spring of great length so that the few turns made in raising or lowering the sash
will only produce a small proportional change in the tension of the spring which
may thus so nearly balance the sash in all positions that the slight friction of the
sash in the window frame will be sufficient to prevent it from moving in one or the
other direction according as its weight is slightly overbalanced or underbalanced
by the tension of the spring

page_text: '
When, however, the sash runs very smoothly (as it is desirable to have it do) the
friction is insufficient to overcome the variations in tension of the spring and con-
sequently a very smoothly running spring balanced sash will fail to remain in its
highest and lowest positions unless some fastening is used, and one object of the
present invention is to provide a spring balanced sash that will be so nearly
balanced as to run easily in either direction throughout the length of its guideway,
but will remain in any position in the guideway until positively moved therefrom
by the operator.
This result is effected in accordance with the present invention by the combination
with the winding reel for the sash suspender, and the spring tending to rotate the
same in the direction to wind the suspender and raise the sash, of a brake or
friction device affording a slight resistance to the rotation of the reel in either
direction, the said resistance being slightly greater than the force tending to turn
the reel due to the difference between the pull of the weight of the sash thereon,
and the opposing action of the spring when under maximum or minimum tension.
Thus, if the spring slightly overbalances or slightly underbalances the weight of
the sash, the resistance of the brake will be sufficient to prevent the latter from
moving under the excess of force in either direction, although such brake resistance
is so slight as to be scarcely felt by a person desiring to raise or lower the sash;
and, being of course less while the sash is in movement, than when it comes to rest,
the effect of the brake upon the movement of the sash by the operator is scarcely
appreciable although it is ample to prevent the sash from moving after it has once
been brought to rest at any desired point, until an extraneous force is again
applied to it.
In the employment of spring balancing devices for window sashes some difficulty
is experienced in properly adjusting the tension of the spring when applied to the
sash in the building where it is to be used, and the present invention consists further
in providing a spring sash balance of the kind described with a temporary fastening
to hold the spring under tension so that the spring can be wound to a definite point
at the place of manufacture, suitable to balance a sash of any given weight as may
be ordered, and may be fastened at the proper point and retained under this degree
of tension until put in place in the building and connected with the sash, when
the temporary fastening may be removed and the sash will be found to be properly
balanced.
A further object of the present invention is to provide means for adjusting the
tension of the counterbalancing spring in case it should become weaker after a
period of use so that it might fail to hold the sash in its highest position in the
frame, that being the point at which the spring is weakest. To attain this object
the apparatus includes an adjustable winding attachment or take-up for the lower
end of the suspender connected with the sash, by which the lower end of the
suspender may, if found necessary, be wound or drawn off from the spring actuated
reel and taken up at the sash.
Such drawing off of the suspender from the winding reel will rotate the latter
against the stress of the spring and thus bring the spring to a higher state of
tension with the sash at any given height than it was before the suspender was
thus wound off from the reel and taken up at its point of connection with the
sash.
The winding or take up connection at the sash consists of a spool with which
the lower end of the sash suspender is connected so that it can be wound thereon,
said spool being provided with a worm gear and worm.meshing with said gear for
turning the said spool so that the lower end of the suspender may if found necessary
be unwound or drawn off from the spring actuated lever and taken up at the sash.
The worm for turning the winding spool in the sash is provided with a key shaft
adapted to be operated by a key or winding handle applied through a suitable hole
in the sash and as the adjustment needs to be made only at long intervals if at all,
the key-hole may if desired be concealed by the inside or parting bead of the sash

page_text: frame which may be removed when the adjustment is to be made, or the key-hole
may be in such position as to be accessible without removing the beading strips,
either at the front of the stiles or at the top of the sills of the sashes.
It is desirable in some cases to sò construct the sash balancing mechanism that
it can be applied to sash frames and meshes of different widths. To accomplish
this object the invention further consists in a novel construction of the shaft for
transmitting the force from the counterbalancing spring to the pullies and the sash
suspenders so that the shaft can be varied. or adjusted in length but made
substantially rigid when so adjusted so as to operate effectually in the apparatus.
The shaft is composed of two or more parts one mortised, grooved, or recessed to
receive a corresponding portion of the other which can be inserted to a greater or
less extent to thus vary the effective length of the two engaged parts.
The recessed part is provided with an external screw-thread, and the recess or a
portion thereof constitutes a groove in the periphery of the threaded part, and the
other member has a corresponding rib which enters the said groove and is provided
with portions of screw threads which will coincide and become practically
continuous with the thread on the other portion of the shaft, which is provided
with a nut or internally threaded sleeve that can be run on to the coinciding threads
of the two parts of the shaft and will thus lock them firmly against longitudinal
movement.
Preferably two such nuts are employed so that they can be jammed together to
prevent accidental displacement and hold the two parts of the shaft firmly.
This invention also comprises a sash fastener adapted to engage with and lock
each sash at any desired position in its run so that either or both sashes may be
left part way open for ventilation but securely locked against further opening
movement.
The fastening comprises a toothed locking bar fixed to the stile of each sash, the
one on the lower sash or front sash being on the rear edge of the stile thereof, next
to the parting bead, and extending downward from the top of the sash, while the
locking bar on the upper sash or rear sash is near the front of the stile and con-
sequently also near the parting bead and it extends upward from the lower edge of
the upper sash. These bars generally need not be over six or eight inches in length
as it is of no advantage to fasten the sashes if they are to be left open more than
six or eight inches each, and the locking bar on the lower sash has upwardly
inclined ratchet teeth while the one on the upper sash has similar ratchet teeth
but downwardly inclined.
The other member of the fastening is mortised into the casing of the sash frame
at about the level of the meeting rails of the sashes when closed, said fastening
member comprising a pair of dogs or springs actuated pawls one co-operating with
each of the locking bars on the sashes. These pawls work in a frame piece having
a face plate that lies in the sash runs of the window frame one pawl projecting at
cach side of the parting bead, and being of proper shape to prevent upward move-
ment of the lower sash or downward movement of the upper sash by engagement
with the ratchet toothed bars on said sashes.
The pawls are normally pressed outward by a spring but may be retracted so as
not to project from the sash runs when it is desired to unfasten the sashes by means
of a cam operated by a key introduced from the front of the window casing.
Dated this. 6th day of February 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to Appliances for Balancing and
Fastening Window Sashes.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby declare
the nature of this invention, and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement :-
This invention relates to means for balancing the weight of window sashes so
that they will run easily in the sash frames and also for fastening the sashes at any
desired height in the sash frames, the object being to produce a more convenient
and efficient, and at the same time less expensive balance than those now in
general use.
The invention is embodied in a construction in which the weight of the sash is
counterbalanced by the force of a single spring which force is applied to and
divided equally between the two sides of the sash.
The sash balancing mechanism of the present invention comprises a rod or shaft,
preferably above the top member or head of the sash frame (although it may if
desired be placed below the sill) said shaft having fixed to its ends the winding
reels or pulleys, preferably located just over the ends of the sash, to which reels
are connected suspending bands which extend down through openings in the head
of the sash frame and are connected with the side members or stiles of the sash. A
long spiral spring, preferably containing two or more layers of coils, encircles the
said shaft and has one end connected therewith and the other made fast to the
stationary structure so that the force of the spring is applied to rotate the shaft in
the direction to wind the suspending bands thereon and thus having a tendency to
raise the sash, which tendency is substantially sufficient to balance the weight of
the sash leaving it free to move under any extraneous force sufficient to overcome
inertia and friction.
With the mechanism thus far described it is impossible to exactly counterbalance
the weight of the sash in all positions, for, if the spring be of sufficient tension to
hold the sash in its highest position, the winding up of the spring by the lowering
of the sash will so increase the tension of the spring that it will overbalance the
weight of the sash and thus tend to cause the sash to rise while, on the other hand,
if the spring just balances the sash in its lowest position, it will become weaker, by
unwinding, as the sash is raised and thus will not have quite enough tension to fully
balance the sash in its highest position, so that the latter will tend to descend by the
force of gravity.
These objections are largely overcome by employing a multiple layer spiral
spring of great length so that the few turns made in raising or lowering the sash
will only produce a small proportional change in the tension of the spring which
may thus so nearly balance the sash in all positions that the slight friction of the
sash in the window frame will be sufficient to prevent it from moving in one or the
other direction according as its weight is slightly overbalanced or underbalanced by
the tension of the spring.
When, however, the sash runs very smoothly (as it is desirable to have it do) the
friction is insufficient to overcome the variations in tension of the spring and
consequently a very smoothly running spring balanced sash will fail to remain in its.
highest and lowest positions unless some fastening is used, and one object of the
present invention is to provide a spring balanced sash that will be so nearly
balanced as to run easily in either direction throughout the length of its guideway,
but will remain in any position in the guideway until positively moved therefrom by
the operator.

page_text: This result is effected in accordance with the present invention by the combina-
tion with the winding reel for the sash suspender, and the spring tending to rotate
the same in the direction to wind the suspender and raise the sash, of a brake or
friction device affording a slight resistance to the rotation of the reel in either
direction the said resistance being slightly greater than the force tending to turn
the reel due to the difference between the pull of the weight of the sash thereon,
and the opposing action of the spring when under maximum or minimum tension.
Thus, if the spring slightly overbalances or slightly underbalances the weight of
the sash, the resistance of the brake will be sufficient to prevent the latter from
moving under the excess of force in either direction, although such brake resistance
is so slight as to be scarcely felt by a person desiring to raise or lower the sash;
and, being of course less while the sash is in movement, than when it comes to rest,
the effect of the brake upon the movement of the sash by the operator is scarcely
appreciable although it is ample to prevent the sash from moving after it has once
been brought to rest at any desired point, until an extraneous force is again
applied to it.
A further object of the present invention is to provide means for adjusting the
tension of the counterbalancing spring in case it should become weaker after a
period of use so that it might fail to hold the sash in its highest position in the
frame, that being the point at which the spring is weakest. To attain this object
the apparatus includes an adjustable winding attachment or take-up for the lower
end of the suspender connected with the sash, by which the lower end of the
suspender may, if found necessary, be wound or drawn off from the spring actuated
reel and taken up at the sash.
Such drawing off of the suspender from the winding reel will rotate the latter
against the stress of the spring and thus bring the spring to a higher state of tension
with the sash at any given height than it was before the suspender was thus wound
off from the reel and taken up at its point of connection with the sash.
The winding or take up connection at the sash consists of a spool with which the
lower end of the sash suspender is connected so that it can be wound thereon, said
spool being provided with a worm gear and worm meshing with said gear for turning
the said spool so that the lower end of the suspender may if found necessary be
unwound or drawn off from the spring actuated lever and taken up at the sash.
The worm for turning the winding spool in the sash is provided with a key shaft
adapted to be operated by a key or winding handle applied through a suitable hole
in the sash and as the adjustment needs to be made only at long intervals if at all,
the key-hole may if desired be concealed by the inside or parting bead of the sash
frame which may be removed when the adjustment is to be made, or the key-hole
inay be in such position as to be accessible without removing the beading strips,
either at the front of the stiles or at the top of the sills of the sashes.
It is desirable in some cases to so construct the sash balancing mechanism that it
can be applied to sash frames and sashes of different widths. To accomplish this
object the invention further consists in a novel construction of the shaft for trans-
mitting the force from the counterbalancing spring to the pulleys and the sash
suspenders so that the shaft can be varied or adjusted in length but made
substantially rigid when so adjusted as to operate effectually in the apparatus.
The shaft is composed of two or more parts one mortised, grooved, or recessed to
receive a corresponding portion of the other which can be inserted to a greater or
less extent to thus vary the effective length of the two engaged parts.
The recessed part is provided with an external screw-thread, and the recess or a
portion thereof constitutes a groove in the periphery of the threaded part, and the
other member has a corresponding rib which enters the said groove and is provided
with portions of screw threads which will coincide and become practically continuous
with the thread on the other portion of the shaft, which is provided with a nut or
internally threaded sleeve that can be run on to the coinciding threads of the two
parts of the shaft and will thus lock them firmly against longitudinal movement.

page_text: Preferably two such nuts are employed so that they can be jammed together to
prevent accidental displacement and hold the two parts of the shaft firmly.
This invention also comprises a sash fastener adapted to engage with and lock
each sash at any desired position in its run so that either or both sashes may be
left part way open for ventilation but securely locked against further opening
movement.
The fastening comprises a toothed locking bar fixed to the stile of each sash, the
one on the lower sash or front sash being on the rear edge of the stile thereof, next
to the parting bead, and extending downward from the top of the sash, while the
locking bar on the upper sash or rear sash is near the front of the stile and conse-
quently also near the parting bead and it extends upward from the lower edge of
the upper sash. These bars generally need not be over six or eight inches in
length as it is of no advantage to fasten the sashes if they are to be left open more
than six or eight inches each, and the locking bar on the lower sash has upwardly
inclined ratchet teeth while the one on the upper sash has similar ratchet teeth but
downwardly inclined.
The other member of the fastening is mortised into the casing of the sash frame
at about the level of the meeting rails of the sashes when closed, said fastening
member comprising a pair of dogs or springs actuated pawls one co-operating with
each of the locking bars on the sashes. These pawls work in a frame piece having
a face plate that lies in the sash runs of the window frame one pawl projecting at
each side of the parting bead, and being of proper shape to prevent upward
movement of the lower sash or downward movement of the upper sash by engage-
ment with the ratchet toothed bars on said sashes.
The pawls are normally pressed outward by a spring but may be retracted so as
not to project, from the sash runs when it is desired to unfasten the sashes by
means of a cam operated by a key introduced from the front of the window
casing.
In the accompanying drawing
Figure 1 is a front elevation of a sufficient portion of a sash frame, sash, and
balancing mechanism therefor to illustrate this invention.
Figure 2 is an end elevation thereof partly in section,
Figure 3 is a detail of the tension-adjusting devices hereinafter referred to.
Figure 4 is a sectional view showing a modified arrangement of the tension
regulating device,
Figure 5 is a perspective view of the sash fastening device detached,
Figure 6 is a sectional detail showing the sash fastening device in side elevation,
Figure 7 is an horizontal section through the sash fastening device on line 7,
Figure 1,
Figure 8 is a longitudinal vertical section of the fastening device on line 8,
Figure 7.
Figure 9 is a side elevation of the adjustable shaft employed in this invention.
Figure 10 is a transverse section thereof, and
Figures 11 and 12 are similar views showing a modified construction of the
adjustable shaft.
As shown in this instance, the sash balancing mechanism is applied above the
head or top member A of the sash frame and comprises shafts a one for each
sash B, B2, the said shafts running in bearings in brackets b (see Figure 2),
fastened upon the head A of the sash frame near each end thereof.
The balancing mechanism for each of the two or more sashes is the same, and it
will consequently be necessary to describe the mechanism of one sash only.
The shaft a has fixed upon each end thereof a pulley winding reel c upon which
are wound the sash suspenders which are shown as thin metallic bauds d one end of each
of which is connected as shown in Figure 2, with a stud c² on the face or web of the
corresponding reel from which stud the band extends through a notch in the
grooved periphery of the pulley on which it winds and from which it extends as

page_text: shown in this instance over a guide pulley 62 on the bracket b through an openin
in the head of the sash frame down to the sash to the stile of which the other end
of the said sash suspending band is connected as will be described.
The counterbalancing force is derived from a spring C preferably in the form of
a long spiral spring encircling the shaft and made up of two or more concentric
layers of coils one end of the said spring being made fast to the shaft a as by
passing it through a transverse slot or perforation therein as shown at C², while the
other end is made fast to some part of the stationary structure shown in this.
instance as a pin or stud 63 on one of the brackets b.
The spring C is strained enough to exert a force tending to turn the shaft a in
. one direction about equal to the tendency of the weight of the sash on the bands d
to turn it in the other direction, but as the full travel of the sash from top to bottom:
of the window frame will cause the shaft a to make several revolutions there will be
a corresponding tightening up or increase of tension of the spring as the sash moves.
downward or decrease as the sash moves upward so that if for example the tension.
of the spring exactly balances the sash when midway in its run way, the spring will
necessarily slightly overbalance the sash in its lowest position and slightly under-
balance it when in highest position. If therefore, the sash should run very
smoothly in its guides it might drop a little from its highest position or run up a
little from its lowest position owing to the variation in the strain of the spring..
To prevent such rising or falling of the sash, the balancing mechanism is provided
with a brake or friction device shown as a disk D see Figure 1, which is slightly
dished so that its periphery presses laterally against the periphery of the adjacent
pulley while the central portion of the disk pressed laterally against the bearing.
bracket b and said friction disk is prevented from rotating with relation to the said
bracket by a suitable key or fastening so that it produces a frictional resistance to
the rotation of the pulley c in either direction. The friction disk D is shown as
radially slotted at D², to render it more -yielding and its pressure should be such
that the frictional resistance to rotation of the pulley c is somewhat in excess of the
tendency to rotate the same due to the maximum difference between the weight of
the sash tending to turn the pulley in one direction and the opposing force of the
balancing spring C tending to turn it in the opposite direction.
Thus the brake will prevent the shaft from turning, with a corresponding rise or
fall of the sash, owing to the variation in the strain of the spring but inasmuch as
the spring is very long and its variation of tension is very small the friction need
not be very great and will not afford an objectionable resistance to the movement
of the sash by the operator, being in fact scarcely felt while the sash is being
raised or lowered.
Means are provided for adjusting the tension of the balancing spring C if it
should weaken from a long period of use. Such adjustment if effected by con-
necting the lower end of the sash suspenders d with an adjustable attaching
device or take-up best shown in Figures 1 to 4, properly secured to the stile or
other suitable part of the sash. The said take-up consists of a small reel .or
spoolf journalled in suitable bearings in the frame piece f2 that may be let into.
the wood of the sash, as shown in Figures 1 and 2, and fastened therein by screws.
or otherwise, the end of the suspenders d being connected with said winding spool
as shown in Figure 3, by passing through a slot therein.
In order to provide for the rotation of the spool fit is as shown in this instance
provided with a worm gear f³ meshing with a worm g as best shown in Figure 2,
also turning in suitable bearings in the frame piece f₁ and provided with means
for rotating the same as for example the squared arbor 92 to be engaged by a
key introduced through a suitable hole in the sash as shown in Figure 2.
The key-hole may either be in such location as to be concealed behind the
bead A of the sash frame, which would then have to be removed in order to
permit the key to be applied for the purpose of adjusting the sash suspender; or
by properly constructing the frame and working parts the said key-hole may
either be accessible at the front of the sash or if preferred from the top of the

page_text: •
1
I
sash rail as shown in Figure 4. The thread of the worm g is of such pitch that it
cannot be rotated by the pressure of the teeth of the worm gear and will thus
remain in whatever position it is left by the key. If at any time it should be found
that the spring C of the balancing mechanism was not strong enough to hold the
sash in its highest position in the frame so that the sash would drop by its weight
an inch or two for example to the position with relation to the top of the window
frame shown in Figure 2, the key could be applied to the take up device and the
latter operated to wind the band d upon it which operation would raise the sash to
the top of the frame if the reel c remained, stationary during the operation; or,
what amounts to the same thing, if the sash remained stationary the operation
would unwind a corresponding portion of the suspender d from the reel c thus
turning the latter against the stress of the spring C and thereby tightening the
said spring so that it would exert greater force and would consequently counter-
balance the sash when pushed clear to the top of the frame. It is of course
necessary to provide a sufficient length of the suspender d to enable a portion of it
to be thus unwound from the reel c and wound upon the reel when required to
adjust the spring C and yet leave enough on the reel e to permit the sash to be
moved down to its lowest position.
It is obvious that if the balancing spring, should be rendered too strong by
adjustment or otherwise, the reverse adjustment might be made by unwinding a
portion of the lower end of the band from the take-up spool fand thus permitting
the spring C to wind the corresponding amount upon the reel e thus relaxing and
thereby reducing the strength of the spring.
1
In case the sash suspender becomes stretched or lengthened by use, the sash
can be properly adjusted by winding a portion of the lower end of the suspender
on to the take-up spool f.
Where two tapes or suspenders are used to support the sash and two of the
tension regulators are employed, it is obvious that by adjusting one or both of them
the length of the suspenders can be altered so as to compensate for unevenness in
their length, and that thereby the sash may be properly hung.
The sash fastening is best shown in Figure 1 and Figures 5 to 8 inclusive. It
comprises a locking member k see Figures 1, 6, and 7, at the rear corner of the
stile of the lower sash B and a similar locking member 2 at the front inside edge
of the upper sash B², said members consisting of ratchet toothed bars of a length
equal to the greatest distance that it is desired to open the sashes and fasten them
against further movement. It is obvious that the bars might extend the entire
length of each sash; but usually a length of five or six inches will be sufficient
for all practical purposes. Each bar has teeth of ratchet shape, those on the lower
sash inclining upward, and those on the upper sash inclining downward and the
said bars are adjacent to and one at the front and the other at the rear of the
parting bead A3, of the sash frame. These locking bars co-operate with the other
member of the fastening which is mortised into the side member or casing A of
the window frame, and comprises two dogs or pawls m m², see Figures 5 and 7,
.connected with a U-shaped piece or pawl carrier m³ working in guides in a frame
piece having a face plate which is let into the face of the casing A* of the sash
frame under the parting bead A³ as best shown in Figure 7. The face plate n is
thus flush with the runway or surface of the casing A on which the sashes are
guided in their up and down movement, and the pawls m, m2 are in line with the
locking bars k, k², that is, one at the front and the other at the rear of the parting
: bead A³ which may extend across the front of the face plate n. Each pawl m, m²
is properly inclined to co-operate with the corresponding locking bar
or 2, the
pawl m for example engaging with the teeth of the bark so as to prevent upward
movement of the lower sash B while the pawl m² engages with the bar k² so as to
prevent downward movement of the upper sash B so that both sashes are securely
locked against further opening movement at whatever position they may be when
the pawls m, m2 are thrown into engagement with the bars k, k². The said
pawls m, m² are thrown outward at the proper time to engage with the bars k²

page_text: by means of a spring m' which bears against the rear side of the U-shapeu pawr
carrier m³ and thus presses the pawls m, m2 outward so that they project from the
face plate n although they can yield inwardly, and will thus prevent a downward
movement of the lower sash or upward movement of the upper sash while permitting
movement of either sash in the opposite direction.
In order to unlock the sashes so that they may run up or down freely, the
pawls m, m2 are retracted-so as not to project beyond the face plate n by means of
a cam or eccentric o (see Figure 8) fastened to a shaft o² and working between the
guide projections n' at the rear of the face plate n in which the pawl carrier m³
operates. The shaft o' of the cam o is provided with a squared hole or otherwise
properly shaped to be engaged by a key o³ see Figure 7, which may be inserted
through an opening o' at the front of the window frame (see Figure 1) and the
said eccentric is in position to engage with the rear portion of the pawl carrier m³
so that when turned to the position shown in dotted lines Figure 8, it will force
the pawls backward or inward against the stress of the spring m' thus disengaging
the pawls from the locking bars k, k³ and leaving the sashes free to run. The
pawl carrier m³ is slotted where it is traversed by the key o³ as best shown in
Figures 5 and 6, so as to permit the movement of the pawl carrier in its guides,
and the cam o is flattened or recessed at the point of greatest throw or eccentricity
as shown in Figure 8 to prevent accidental turning after it has been brought to
the position to fully retract the pawls m, m³. With the camo in the position
shown in full lines Figure 8 the pawls m, m2 are under control of the springs m
and will engage with the locking bars k, k³ at each tooth thereof and while
permitting a closing movement of either sash will prevent any opening movement
thereof but with the said cam turned half around to the position shown in dotted
lines Figure 8 the pawls are retracted and the sashes are unlocked and may be
moved up and down freely as required. The locking bars k, k² overlap one another
slightly when the sashes are fully closed, and the herein described sash fastener
forms an efficient lock to hold the sashes fully closed as well as to fasten them
when open a short distance.
In order to enable a sash balancing mechanism of the kind herein specified to
be applied to windows of different width without necessarily making the shaft a of
the exact length for each window to be fitted the said shaft may be made
adjustable in length by the construction illustrated in Figures 9 to 12, which is as
follows:-
The shaft is composed of two parts a, a which are to be connected in such
manner that their engaging portions can be overlapped a greater or less extent to
vary the effective length of the two connected parts, and when thus overlapped are
to be securely held together so as to constitute a substantially rigid shaft capable
of transmitting torsional or other desired movement.
'
In the construction shown in Figures 9 and 10, the part a is provided with two
longitudinal slits a³ intersecting one another at right angles and cut wholly through
the shaft as shown, while the other member a has a portion at of the same
sectional shape as the recess as of the part a thus forming a cross shaped tenon which
The said tenon can be
enters the corresponding cross shaped recess a³ in the part a.
inserted to a greater or less extent in the said recess according as the length of the
entire shaft is to be greater or less, and in order to rigidly lock or secure the parts
against relative movement after they are once properly adjusted, or overlapped the
amount necessary to give the required length to the shaft, the recessed portion a is
provided with an external screw thread as shown, and the projections at of the
part a have corresponding screw thread portions which thus coincide with and
complete the thread of the portion a in that part which is entered by the said
tenon a' of the part a². A nut or internally threaded sleeve a' and preferably a
second nuit a to co-operate therewith as a check nut are fitted upon the thread of
the shaft a and by running the said nuts off from the recessed portion a of the
shaft the tenon portion at of the shaft can be inserted to any desired distance, an
stopped with its thread portions in coincidence with those on the part a after which
B

page_text: "
the nut a can be turned on to the overlapping parts of the shaft and by its
engagement with the threaded portions of each will prevent further longitudinal
movement of one with relation to the other, and by turning the two nuts a³, a firmly
against one another the two parts of the shaft can be locked very rigidly together
so as to operate substantially as a solid shaft for any purpose that may be desired.
In the construction shown in Figures 11 and 12, the recessed part a is for the
most part cylindrical making a portion of the part a tubular but there is a slot a20
cut through to the periphery of the recessed part of the shaft a which is externally
threaded, and the other portion a' of the shaft besides having a cylindrical tenon
to fit the bore of the shaft a also has a rib a2 which fills the slot a2 and is provided
with thread portions to coincide with and complete the thread on the other part of
the shaft, so that the two parts may be adjusted and then locked against further
relative movement, by nuts a³, as, as described in connection with the construction
shown in Figures 9 and 10.
In the construction shown in Figure 11, the adjustment of the shaft must be in
steps each of which is equal to the distance between two consecutive turns of the
screw-thread; but with the construction shown in Figure 9, i.e. when the slot or
slots are cut diametrically through the shaft, or the latter has more than one
longitudinal groove in its periphery, a more minute adjustment may be made if
necessary by wholly withdrawing the portion a' from the portion a and turning the
former quarter around in one or the other direction or half around before
re-inserting it, by which plan, the adjustment of length of the shaft may be made
to within one-fourth of the distance between two turns of the thread, so that if for
example, the thread is one of twenty-five turns to the inch the length of the shaft
may be adjusted to within one-hundredth of an inch...
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
1. A sash balancing mechanism comprising a shaft extending transversely to
the sash frame and suitable bearings for said shaft, winding reels fixed to the
ends of said shaft, and sash suspenders each having one end connected to the
corresponding winding reel and the other with one end of the sash to be balanced,
and a balancing spring having one end connected with the said shaft and the other
with the framework and a brake affording resistance to the rotation of said shalt
in either direction, substantially as and for the purpose described.
2. The combination with a spring actuated sash suspender of a take-up spool
adapted to be secured to the sash and have the lower end of said suspender
connected therewith and wound thereon, a worm gear connected with the said
spool and a worm meshing therewith provided with a key shaft accessible through
an opening in the sash, substantially as and for the purpose described.
3. A sash fastener comprising a ratchet toothed locking bark having upwardly
inclined teeth on the lower sash and a ratchet toothed locking bark having
downwardly inclined teeth on the upper sash, combined with a fastening member
adapted to be secured in the casing of the sash frame having pawls to co-operate
with said locking bars, a spring to throw said pawis. outward into engagement
with said locking bars, and a retractor to withdraw the said pawls from engage-
ment with the locking bars, substantially as described.
4. In a sash balancing mechanism an adjustable shaft made up of two parts
one having a longitudinal recess and the other a córresponding tenon to be inserted
any desired distance in said recess, the recessed portion being externally threaded
and having a longitudinal groove cut through its threaded periphery, and the
tenon portion fitting the said groove and having threaded portions coinciding with
the thread on the recessed part, and an internally threaded nut or sleeve co-operating
with said threaded portions, substantially as described.
5. In a sash balancing mechanism a shaft composed of two parts one screw-
threaded and provided with longitudinal slots cut' diametrically through the same,

page_text: and the other having a corresponding tongue or tenon fitting said slots and having
thread portions coinciding with those of the slotted part, combined with a threaded
nut co-operating with the said threaded portions, substantially as
sleeve or
described.
Dated this at
f Novemben 1001
HASELTINE LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.