Year: 1886

page_text: Date of Application, 1st Oct., 1886
Complete Left, 30th June, 1887
Complete Accepted, 27th Sept., 1887.
My improvements, which are applicable to all kinds of saws, relate :-
1st. To the tension of the blades.
2nd. To the fixing of the blades.
3rd. To the mode of connecting the arms to the strut.
--
And in order that my invention may be fully understood, and readily carried into
effect, reference is had to the accompanying drawings and to the letters of reference
marked thereon.
In Figures 1 to 10, of Sheet 1, I have shewn a saw with one blade, fitted with my
improvements. The blade A is fixed between the ears B B¹ of the trunnions, formed
here by the juxtaposition of the two half round parts CC. Between the ends of the
lower trunnion is rivetted a cross piece D which rests upon a toothed or indented
plate E furnished with ears E¹ E" which clamp the arm of the saw.
A hole passes
through the centre of this toothed or indented plate through which the trunnion passes.
The upper trunnion is prolonged and fitted into a handle F. This handle is fitted at
its lower end with a socket F", toothed upon its face, which is in contact with a
toothed or indented plate E similar to that at the lower part of the saw. Figure 4
shews the underside of the socket F¹.
The strut is connected to the arms by the arrangement shewn in front view Figure 1,
and in side view Figure 5.
The head of the bolt G is furnished with a small projection, which enters or pierces
the strut, and prevents the bolt turning. The washer G here acts as nut, and allows
of tightening as desired. The bolt does not enter the arm, so that in loosening the
washers G the strut can be pushed backwards or forwards.
The hinder part of the saw is provided with a tightener or tension apparatus here
shewn in an overhanging position. This tightener or tension apparatus is composed
essentially of a base plate 1, fixed by one or more screws to the arm of the saw. This
plate fits on the arm by means of two flanged parts, and is turned up at its end so as
ID 0. 527

page_text: to form two ears I which carry an axle J. Upon this axle turns the bell crank lever K
of which the branch K¹ is jointed to two connecting rods K" K" united at their lower
part by a cross bar K. A nut L allows the lengthening or shortening at will of the
portion L of the rod comprised between the cross bar KTV, and the lower arm of the
in which latter the rod is held by means of a head formed at its end by folding
saw,
it over.
Figure 6 shews the tension apparatus out of action, or open, and Figure 1 shews it
closed. It will be seen that on lowering the lever K upon the arm, the axis of the
arm K of the lever, will assume a position a little to the left of the perpendicular
through the axle J, and that the traction exercised by the rod L' tends to prevent the
stretcher opening.
My combination of trunnion and toothed or indented plates allows, on opening the
tension apparatus, of the blade of the saw being placed at any angle with the arm
desired, and in closing the tension apparatus it will be maintained in that position.
Figures 11, 12, 13, 14, and 15 represent a saw with two blades. The blade A is
held at top and bottom between the two plates C₁ C forming trunnions, holding at
their opposite ends the cross pieces D lying in the teeth of the toothed plates E E
placed in the shoes F F. Projections F1 F1 passing through the sides of the caps
prevent the toothed plates turning. The other side of the saw furnished with a fret
saw blade is provided with a tension apparatus analogous to the preceding, except
that the shoe G is substituted for the connecting rods K" K of the preceding
example. The blade is pierced with holes at its extremities in which is passed a
gudgeon fixed upon a spring K. The curved part of the spring serves to raise and
discharge the gudgeon. The same arrangement is repeated at top and bottom. The
blade A can thus be lengthened or shortened at will after having opened the tension
apparatus.
Sheet 2. Figures 1, 2, 3, 4, shews a saw with two blades in which the tension is obtained
by turning, in a convenient manner, the strut A in the upper part of which enters
and turns therein the screw B connecting it with the part C. Here the trunnions of
the saw are solid, the one D carries a thread in which is screwed the handle F, of
which the socket G is toothed upon its lower face. The sawing blade is held between
the ears H connected to trunnions by a screw. The fret saw blade is connected to its
trunnions at one end as shewn in Figure 4 by means of a screw passing through the
trunnion and the saw,
and at the other end as shewn in Figure 3 by means of a
gudgeon K formed by a projection upon a flat part of the trunnion, upon which rests
the end of the saw, and by a hook L which passes under this gudgeon.
Two of the teeth of the trunnion are prolonged to form a key and facilitate the
working of the blade.
Figures 5 and 6 shew the saw furnished with a horizontal tension apparatus. One
of the ends of the fret saw blade is held by means of a gudgeon and hook, the other
enters between the cheeks of two plates bored with holes and holding at opposite end
a cross piece in form of key resting upon the toothed plate. A screwed pin passing
through two holes of the plates, and through that of the blade screws in a threaded
socket M which is itself prevented turning by being formed with the angle or bent
piece M¹.
Sheet 3. Figures 1 to 27 represent modifications of different parts of my saws.
Figures 1 and 2 represent front and sido views respectively of a means of attaching
a tension bar to the extremity of the arm of the saw. This bar is formed with a head
which rests проп
the lower part of the shoe. The other end of the bar may be screw
threaded and held by a nut resting upon the bottom of the the lower shoe. In turning
the nut in any convenient manner the bar is lengthened or shortened at will, and thus
the degree of tension of the blade is regulated.
Figure 3 represents a side view open, Figure 4 a side view closed, and Figure 5 a
front view of another form of tension apparatus. It is composed of a lever A turning
upon axle B supported by the cheeks of a shoe C. At the end of the lever A is
pivotted, by means of an axle D, the stirrup E. In the bottom of the stirrup passes
the screw threaded bar which is held there by the nut G.

page_text: It will be seen that in lowering the lever A, the-axle D is raised and will be placed
above, and to the left of the axle B. The stirrup E is consequently raised, and it
causes a tension on the rod F.
Figures 7 and 8 are front and side views of a flat trunnion fitted with cross-piece K
placed upon the toothed plate shewn here overhanging the end of the arm of the saw.
The cross piece K turns upon its axis K' to enable it to be placed in a vertical position
to allow of it passing through the aperture in the toothed plate.
Figures 9 and 10 shew an arrangement of the ears L forming trunnions, with cross
piece L. The toothed plate is supported by the shoe M in which it cannot turn.
Figure 11 shews a tension apparatus, in the stirrup of which the tension rod is held
by a head taking between two rivets or screws.
Figures 12 and 13 shew an arrangement for fixing the blade of the saw to the
trunnion.
The trunnion is formed with a flat part upon which is arranged the two projecting
parts O. The blade of the saw is furnished at its end with a T piece, the head of
which rests upon the projections 0 0.
A swivel P keeps the saw in position.
Figure 14 is a horizontal section through Figure 12.
Figure 15 is a side view, and Figure 15 a section through Figure 15, of another
arrangement of fixing the fret saw blade. The trunnion Q is prolonged at its lower
part by two cheeks QQ separated by a piece Q of varying thickness, which takes
against the back of the saw. The cheeks Q' as well as the piece Q" are traversed by
a rivet at the bottom, and a screw at top. Oscillating upon the screw there is a
strap Q which carries at its end a movable catch furnished, upon the edge facing
the
saw,
with a tooth which takes into a tooth of the saw.
In this arrangement is combined the tension arrangement. This being closed, the
catch is forced against the saw; when it is open, on the contrary, the saw can be
raised as desired. This arrangement is adapted for holding saws of various sizes.
Figures 16 and 17 shew an arrangement for holding the tension rod without using
nuts and screws. A shoe carries two parallel plates R' R' bored with holes opposite
one another. The head of the tension rod engages between these plates, and is held
in position by the piece shewn separately Figure 18. This piece is formed of a plate
holding two gudgeons placed between two holes of the plates R¹ R¹. A swinging
hook (rivetted or screwed) holds the plate in front. The head of the tension rod rests
upon the two gudgeons.
Figure 19 shews the saw held in a slot in a trunnion with plain teeth, of which two
teeth are prolonged and form a key.
Figure 20 shews the trunnion with screwed teeth supported upon a toothed plate
which is here shewn in an overhanging position, but which may be placed in any of
The trunnion is
the positions above described. Upon this trunnion travels a fly nut.
formed with a longitudinal slot in which moves the cross piece K fixed at the end of
the saw blade. On turning the nut one way or the other the blade of the saw is
tightened or loosened.
Figure 21 shows a modification of the tension apparatus shewn in Figure 1.
Sheet 2. Here the upright does not act as a nut, it is simply bored with a hole,
and it is an independent nut which upon raising or lowering the screw works the
tension.
Figure 22 shews tension apparatus similar to that in Figures 1 and 6, Sheet 1, but
not placed in an overhanging position.
Figures 23 and 24 shew a mode of attaching the tension rod, the head of which
rests between two plates T T upon two rivets or screws T¹ T₁, the ends opposite these
plates are fixed at the desired lieight to a rack with holes T suspended
a shoe.
Figures 25 and 26 show an arrangement of fixing the blades by means of two
plates U U, bent over or flanged at their upper part and held connected by a plate U'
grooved as shown in Fig. 26, and which is rivetted to the flanges or bent parts.
This plate is placed in position by being passed through the opening made in the
plates U.

page_text: This opening allows of the blade being employed in three ways :-
1. It is placed as shown in the drawings.
2. It can be placed at right angles by screwing the arms of the saw in this opening.
3. It will serve as a hand saw (passe partout) by taking it out of the frame. These
openings then serve as a handle.
Figure 27 is a modification of the tension apparatus shewn in Figure 21. The nut
instead of having wings carries an arm of any desired length. This tension apparatus
I preferably employ for large saws.
The tension rod in large saws is formed of two strips of wood stiffened internally by
metal. This arrangement is adopted in cases where the workman holds the saw by
the tension rod.

page_text: I, FRANCOIS CÉSAIRE PROUVAY of 2 Rue Ste. Appoline, Paris, France 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:-
My improvements, which are applicable to all kinds of
1st. To the tension of the blades.
2nd. To the fixing of the blades.
saws, relate:
3rd. To the mode of connecting the arms to the "strut" or upright.
-
And in order that my invention may be fully understood reference is had to the
accompanying drawings and to the letters of reference marked thereon. In all the
figures the letters of reference thereon only refer to that particular figure.
In Figures 1 to 10 sheet 1, I have shewn a saw with one blade fitted with my
improvements. The blade a is fixed between the ears 6, 6' of the trunnions formed
here by the juxtaposition of the two half round parts c, c'. Between the ends of the
lower trunnion is rivetted a cross piece d which rests upon a toothed or indented
plate e furnished with ears e¹ e¹¹ which clamp the arm of the saw.
A hole passes
through the centre of this toothed or indented plate through which the trunnion
passes. The upper trunnion is prolonged and fitted into a handle f. This handle is
fitted at its lower end with a socket f¹, toothed upon its face which is in contact with
a toothed or indented plate e similar to that at the lower part of the saw.
Figure 4 sheet 1 shews the underside of the socket f¹.
The strut is connected to the arms by the arrangement shewn in front view
Figure 1, and in side sectional view Figure 5 sheet 1. The head of the bolt g is
furnished with a small projection, which enters or pierces the strut and prevents the
bolt turning. The washer g¹ here acts as nut and allows of tightening as desired.
The bolt does not enter the arm so that in loosening the washers g¹ the strut can be
pushed backwards or forwards. The hinder part of the saw is provided with a
tightener or tension apparatus here shewn in an overhanging position. This tightener
or tension apparatus is composed essentially of a base plate i fixed by one or more
screws to the arm of the saw. This plate fits on the arm by means of two flanged
parts, and is turned up at its end so as to form two ears which carry an axle j.
Upon this axle turns the bell crank lever k of which the branch is jointed to two
connecting rods k, k united at their lower part by a cross bar V. A nut / allows
the lengthening or shortening at will of the portion of the rod comprised between
the cross bar and the lower arm of the saw, in which latter the rod is held by
means of a head formed at its end by folding it over.
Figure 6 sheet 1 shews the tension apparatus out of action or open, and Figure 1
shews it closed. It will be seen that on lowering the lever k upon the arm, the
axis of the arm k of the lever will assume a position a little to the left of the per-
pendicular through the axle j and that the traction exercised by the rod tends to
prevent the stretcher opening.
My combination of trunnions and toothed or indented plates, allows, (on opening

page_text: the tension apparatus), of the blade of the saw being placed at any angle with the
arm, desired, and (on closing the tension apparatus) it will be maintained in that
position.
Figures 11, 12, 13, 14 and 15 sheet 2 represent a saw with two blades. The
blade a is held at top and bottom between the two plates c' c forming trunnions,
holding at their opposite ends the cross pieces d, lying in the teeth of the toothed
plates e, e, placed in the shoes ff. Projections f f passing through the sides of
the caps prevent the toothed plates turning. The other side of the saw furnished with
a fret saw blade is provided with a tension apparatus analogous to the preceding,
except that the shoe g is substituted for the connecting rods ", " of the preceding
example. The blade is pierced with holes at its extremities in which is passed a
gudgeon fixed upon a spring k. The curved part of the spring serves to raise and
disengage the gudgeon. The same arrangement is repeated at top and bottom.
The blade a can thus be lengthened or shortened at will, after having opened the
tension apparatus.
Figures 16, 17, 18, 19 sheet 3 shew a saw with two blades in which the tension is
obtained by turning in a convenient manner the strut a, in the upper part of which
enters and turns therein the screw b connecting it with the part c. Here the trunnions
of the saw are solid;-the one d carries a thread in which is screwed the handle f of
which the socket g is toothed upon its lower face. The sawing blade is held between
the ears connected to trunnions by a screw. The fret saw blade is connected to its
trunnions at one end as shewn in Figure 19 sheet 3 by means of a screw passing
through the trunnion and the saw, and at the other end as shewn in Figure 18 sheet 3
by means of a gudgeon formed by a projection upon a flat part of the trunnion,
upon which rests the end of the saw, and by a hook / which passes under this gudgeon.
The toothed head of the trunnion forms a key to facilitate the adjustment of the
blade.
Figures 20 and 21 sheet 3 shew the saw furnished with a horizontal tension
apparatus. One of the ends of the fret saw blade is held by means of a gudgeon
and hook, the other enters between the checks of two plates bored with holes and
holding at opposite end a crosspiece in form of key resting upon the toothed plate.
A screwed pin passing through two holes of the plates and through that of the blade
screws in a threaded socket m which is itself prevented turning by being formed with
the angle or bent piece m².
Figures 22 to 50 sheet 4 represent modifications of different parts of my saws.
Figures 22 and 23 sheet 4 represent front and side views respectively of a means
of attaching a tension bar to the extremity of the arm of the saw. This bar is formed
with a head which rests upon the lower part of the shoe. The other end of the bar
may be screw threaded and held by a nut resting upon the bottom of the lower shoe
as shown at Fig. 27 sheet 4. By turning the nut in the proper direction the frame is
distanced at will, and thus the degree of tension of the blade is regulated.
Figure 24 sheet 6 represents a side view open.
Figure 25 sheet 6 a side view closed, and
Figure 26 sheet 6 an end view of another form of tension apparatus. This stretcher
is composed of a lever a turning upon axle 6 supported by the cheeks of a shoe c.
At the end of the lever a is pivotted by means of an axle d, the stirrup e. In the
bottom of the stirrup passes the screw threaded bar which is held there by the nut g.
It will be seen that in lowering the lever a the axis d is raised and will be placed
above and to the left of the axis b. The stirrup e is consequently raised and it causes
a tension on the rod f.
Figures 28 and 29 sheet 4 are front and side views of a flat trunnion fitted with
crosspiece k placed upon the toothed plate shewn here overhanging the end of the arm
of the saw. The crosspiece k turns upon its axis k¹ to enable it to be placed in a
vertical position to allow of it passing through the aperture in the toothed plate.
l
Figures 30 and 31 sheet 4 shew an arrangement of the ears forming trunnions
with crosspiece. The toothed plate is supported by the shoe m in which it cannot.
turn.

page_text: Figure 32 sheet 4 shews a tension apparatus in the stirrup of which the tension rod
is held by a head taking between two rivets or screws.
Figures 33 and 34 sheet 4 shew an arrangement for fixing the blade of the saw to
the trunnion. The trunnion is formed with a flat part upon which is arranged the
two projecting parts 0. The blade of the saw is furnished at its end with a T piece
the head of which rests upon the projections o o. A safety catch p keeps the saw in
position. Figure 35 sheet 4 is a horizontal section through line 1-2 of Figure 33
sheet 4.
•
Figures 36 and 37 sheet 4 shew a side view and section through line 3-4 of
Figure 36 sheet 4 of another arrangement of fixing the fret saw blade. The trunnion
is prolonged at its lower part by two cheeks g¹g the distancing being effected by
a piece of varying thickness which takes against the back of the saw. The
cheeks q as well as the piece q are traversed by a rivet at the bottom and a screw
at top.
Oscillating upon the screw there is a hinged arm q which carries at its end a
movable toothed pawl, furnished upon the edge facing the saw, with a tooth which
takes into a tooth of the saw. In this arrangement is combined the tension arrange-
ment. This being closed the pawl is forced against the saw; when it is open, on the
contrary, the saw can be raised as desired. This arrangement is adapted for holding
saws of varying breadths.
Figures 38 and 39 sheet 4 shew an arrangement for holding the tension rod
without using nuts and screws. A bracket plate or shoe r carries two parallel
plates bored with holes opposite one another. The head of the tension rod
engages between these plates and is held in position by the piece shewn separately at
Figure 40 sheet 4. This piece is formed of a plate holding two gudgeons placed in
space between and in the holes of the plates. A swinging hook (rivetted or
screwed) holds the plate in front. The head of the tension rod rests upon the two
gudgeons.
Figure 41 sheet 5 shews the saw held in a slot in a trunnion. The toothed head of
the trunnion forms a key to adjust the saw.
Figure 42 sheet 5 shows a trunnion with screwed teeth supported upon a toothed
plate which is here shewn in an overhanging position which may be set as described
with reference to Figure 28 sheet 4 of the drawings. Upon this trunnion travels a
fly nut. The trunnion is formed with a longitudinal slot in which moves the cross
piece k fixed at the end of the saw blade. On turning the nut one way or the other
the blade of saw is tightened or loosened.
Figure 43 sheet 5 shews a modification of the tension apparatus shewn in Figure 16
sheet 3. Here the upright does not act as a nut, it is simply bored with a hole and it
is an independent nut which upon raising or lowering the screw works the tension.
Figure 44 sheet 6 shews tension apparatus similar to that in Figures 1 and 6
sheet 1 but not placed in an overhanging position.
Figures 45 and 46 sheet 6 shew a mode of attaching the tension rod, the head of
which rests between two plates t t upon two rivets or screws t¹ (1 the ends opposite
these plates are fixed at the desired height to a rack with holes t" suspended to a
bracket plate.
Figures 47 and 48 sheet 6 shew an arrangement of fixing the blades by means of
two plates u, u bent over or flanged at their upper part and held connected by a
plate u slotted as shewn in Figure 49 sheet 6 and which is rivetted to the flanges
or bent parts. This plate is placed in position by being passed through the opening
made in the plates u.
This opening allows of the blade being employed in three ways.
1. It is placed as shewn in the drawings.
2. It can be placed at right angles by engaging the arms of the saw into this
opening.
3. It will serve as a hand saw, by taking it out of the frame.

page_text: Figure 50 sheet 6 modification of the tension apparatus shewn in Figure 43 sheet 5.
The nut instead of having wings carries an arm of any desired length. This tension
apparatus I preferably employ for large saws.
The tension rod in large saws is formed of two strips of wood stiffened internally
by metal. This arrangement is adopted in cases where the workman holds the saw by
the tension rod.
At Figures 51, 52, 53, and 54 sheet 7 and 55 sheet 8 I have shewn a single hand
saw fitted with my improvements. This is composed essentially of a support a and of
two arms b c between which the blade of the saw is placed.
The arm b is held to the support a by a bracket piece d fixed to the arm b as shewn
by the drawing or in any other convenient manner and supported by a rod e in a
slot f of the tension rod g; this slot is placed in such manner that the tension bar g is
constantly tending to rest in the position shewn in the drawings. The head of the
tension rod g is placed by its rounded part in the hollow of a bedplate h. The arm b
is besides united to the support a by a spring blade & fixed by one part to the
support a by a screw serving at the same time as an abutment on the arm and at
another part to the arm b by one or several screws. This arrangement is represented
in detail at Figure 55 sheet 8. The arm c Fig. 51 sheet 7 is maintained against the
support a by a bracket plate 1 free to slide on the arm a and by means of a projecting
pin m fixed to the arm c and entering as required into one of the holes of the plate n
fixed to the support a as seen at Figure 51 sheet 7.
Figures 53 and 54 sheet 7 shew detached views of the plate with holes and the face
of the arm c which is applied against the support. The tension of the blade can then
be regulated at will by introducing the pin m into one or other of the holes of the
. platen and then turning down the tension bar g. The saw blade may be placed in
any desired position by the employment of my notched plates before described.
Figures 56 and 57 sheet 8 shew an arrangement wherein the tension bar g resting
as before described in the hollow of a bed plate is united by a screw to the end of a
piece o supporting a stirrup p, the lower part of which forms a plate with notches.
The blade is fixed to the trunnion by a hook as shewn in the drawing. The extent
of tension is obtained by means of a winged nut placed on the support.
Figures 58, 59 and 60 sheet 8 shew an arrangement of stretcher acting on a round
rod. The head of the lever g of the stretcher is formed with two slots in which the
trunnions rest the trunnions of the small piece q having in front a point q'; this
piece through which the rod r passes, terininates in a buckle ring or head and is
placed in a vertical slot of the head. The rod r has one part of it threaded and goes
through a nut s fixed to the bracket plate s¹. To increase or diminish the tension of
the blade the lever g is raised until it abuts on the point q¹ Figure 60, and then this
lever is used as a crank. The nuts being fixed, the effective part of the rod can be
lengthened or shortened according to the direction in which it is turned. Then
bringing down the lever g into the position shewn at Fig. 58 sheet 8 the blade is
stretched to the required extent.
At Figures 61, 62, 63 and 64 sheet 9 I have shewn a saw with a special arrange-
ment for fixing the blade and with vertical tension but it should be well understood
that each of these arrangements can be applied separately to any other kind of saw.
The fret saw blade is held at one of its ends by a piece a made in a piece with the
trunnion and provided with a front groove in which the back of the blade is fitted.
This piece a carries a loop plate, the lower end of which is engaged under a tooth or
in a hollow of the blade of the saw. The lower trunnion c is slit longitudinally and
it is besides provided with a round hole bored in the direction of the slot.
A ring e
bored with two holes diametrically opposite surrounds the end of this trunnion and
receives a screw with a milled head of a diameter small enough to enter the hole.
The end of the blade is introduced into the slot the screw is then turned so as to cause
it to penetrate the hole until it touches the back of the saw.
I have shewn a vertical tension the operation of which will be understood by
reference to the drawing. It is very evident that the different appliances which I

page_text: employ in my system of saws is susceptible of different changes, which I am about to
describe, but always in principle only. Thus for example-
Figures 65, 66, and 67 sheet 10, 68 sheet 12, 69 and 70 sheet 10, 71, 72, and 73
sheet 12, 74 and 75 sheet 10, 76, 97, 98, 99, and 100 sheet 12 shew different arrange-
ments of holding appliances and of tension arrangements which I employ with lever
above the arm.
Figures 77 sheet 10, 78 and 79 sheet 12, and 80 sheet 11 shew arrangements for
tightening the tension bar with a fly nut.
Figures 81, 82 and 83 sheet 11 shew arrangements for tightening up the tension
by means of a lever placed under the arm.
Figures 84 sheet 10 and 85 sheet 11 shew a stop arrangement for the rod of the
tension bar.
Figures 86, 87, 88, 89, 90, 91 and 92 sheet 11 shew an arrangement of saw in
which the support itself acts as a tension medium.
Figure 93 sheet 12 shews an arrangement of ordinary support.
Figures 94 sheet 11, 95 and 96 sheet 12 shew different arrangements of fixing for
the blades of saws with stop for chamfer.
As shewn in the drawing at Figs. 65 to 76 sheets 10 and 12 the principal appliance
for the tightening of the tension bar a is composed of a lever b the head of which is
of cam form and the arm of the said lever 6 terminates in a ring c or any other
equivalent arrangement to facilitate the working. The head of this lever is provided
with two claws as at Fig. 65 sheet 10, to receive the trunnions d, d of a kind of
chain e or strap connected to the tension rod by a stirrup gas at Fig. 65 sheet 10,
or by a screw thread as at Figs. 69 and 70 sheet 10, or it is simply pinned on to the
head of the lever as at Fig. 68 sheet 12. This tension mechanism may take the form
of a hook as at Fig. 71 sheet 12; in this case the lever forms a small crosspiece of a
hooking apparatus h as at Figs. 72 and 73 sheet 12 and the stretcher rod is fixed as
at Fig. 71 sheet 12. The bearing i on which rests the head of the lever may be fixed
on the arm of the saw by a wood screw j as at Figs. 65, 66 sheet 10 or it may simply
be a spur or stud R as at Figs. 74 and 75 sheet 10 in the case of the employment of
the tension hook shewn at Figure 71 sheet 12. This bearing has a rectangular
mortise of suitable dimensions to that of the hook.
Figures 97, 98, 99 and 100 sheet 12 shew arrangements of excentric lever on the
arm of the saw in combination with a bracket piece for keeping the lever in its place
on which the tension rod before mentioned is fixed.
In the tightening up arrangements of the tension bar shewn at Figs. 77 sheet 10,
78 sheet 12 and 79 the stretching is effected by a fly nut 7 and terminating, Figs. 77
sheet 10 and 78 sheet 12, in a stirrup m and the stretching rod y is fixed either as
shewn at Fig. 77 sheet 10 or as shewn at Fig. 78 sheet 12. In the arrangement
shewn at Fig. 79 sheet 12 the tension action has two trunnions n bearing on two
cheeks o holding the arms or support tightened by fly nut or the excentric stretching
lever may be employed as shewn at Fig. 76, sheet 12. The fly nut may be arranged
below with a bracket plate p as at Figure 80 sheet 11.
When the lever for tightening up the tension is placed below the arm it is arranged
so that it is jointed in a bracket plate q as at Figs. 81, 82, and 83 sheet 11; it
receives by a hook r the stretcher rod as at Figs. 81 and 82 or 83. The opposite end
of this rod is held by a simple plate with a spur or stud as at Fig. 84 sheet 10, or by
a tension stirrup as at Fig. 85 sheet 11, the tails of which is furnished with a series
of regulating holes for the passage of the pin or screw t arranged on the bracket u as
at Fig. 85 sheet 11.
The support of the saw may itself form the tension in this case, if it is desired, the
saw may be composed of two blades; for this purpose the upper part of the support
is formed as in Fig. 86 sheet 11 and is engaged on a threaded rod z fixed to the arm,
and the foot is arranged as shewn at Fig. 87 with a pivot and collar y held by a
screw in such manner that the tightening is produced by turning as a nut.
In the arrangement shewn at Figs. 88 and 89 sheet 11 the support does not turn,
the upper arm Fig. 88 is traversed by a rod z having a spreading shoulder provided
B

page_text: with a fly nut 1; this rod screw threaded at its lower part takes into a tapped cap 2
so that by turning the nut the tension is effected; the foot of the upright is for this
purpose provided with a piece, fixed to the lower arm, so that the upright cannot
either turn with the tightening of the nut, nor slide on the arm slot. When the arm
is not in the slot, that is to say, when the saw frame is rectangular I may employ for
the lower arm the arrangement shewn at Fig. 90 sheet 11 which simply prevents the
upright from turning during the tightening of the nut.
-
The fly nut instead of being placed on the arm or rod as in the arrangement shewn
at Fig. 88 sheet 11 may be placed below the said arm as at Fig. 91 sheet 11 as instead
of the fly nut the arrangement shewn at Fig. 92 sheet 11 may also be employed.
When it is not desired to employ an upright or support stretcher I arrange the
upright as shewn at Fig. 93 sheet 12 it is formed with a sort of bracket 3 receiving
the saw arm 4 and with a head 5 of form suitable to receive the support 6.
The blades of the saws are mounted as shewn at Figs. 94 sheet 11, 95 and 96
sheet 12; in the arrangement shewn at Fig. 94 sheet 11 the handle 7 carrying a
rod 8 passes through the arm 9; it is provided with a stirrup or arm 10 which retains
the saw by one of the teeth of the blade. On the top of the arm there is a plate 11
having divisions or serrations in which the spurs on the handle take in such manner
as to maintain the saw to the degree of obliqueness required for the chamfer. In the.
arrangement shown at Fig. 95 the blade of the saw 12 is, bored with a hole to be
able to hook it on the pivot 13 forming a part of the rod 14; it is there maintained
by the shoe 15, fixed by a button. In the arrangement shewn at Fig. 96 sheet 12.
the blade of the saw 16 traverses the arm 17 to engage into a fly nut 18 provided.
with a mortise, or it is there maintained by a screw or pin 19. Each of the two
arrangements equally comprise the arrangement for chamfer to which I have before
referred.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I declare that what I claim is :-
1. In saws, the application thereto of stretching apparatus for the blades consisting
of a cam or eccentric headed lever and acting by traction together with means for
suitably bearing on one rod of the tension all substantially as set forth.
2. The arrangement of support acting itself as a tension appliance together with an
arrangement of distancing by screw and which allows of the mounting of two blades
⚫ on one and the same saw substantially as set forth.
3. The fixing of the blades for which the handle or gripping appliance is arranged
with spurs acting on a plate provided with divisions to give and retain the degree of
desired obliquity to the blade so as to be able to make the required fret cuttings
substantially as set forth.
4. The application to saws of cam lever and arranged substantially as shewn in the
accompanying drawing.
5. The general arrangement, construction and combination of tension sawa
substantially as herein before described and illustrated with reference to the accom-
panying drawings.
:.<
"