FR2837136A3 - Constant tension canvas frame for oil painting is in two parts able to slide in each other and subjected to spring tension over whole periphery - Google Patents

Abstract

The canvas is mounted on a wooden frame in two parts (1bis,4bis) which are able to slide in each other. They are subjected over their whole periphery to the action of springs (14) which tend to separate them. This tensioning stiffens the canvas (11) from a fixed point obtained by nailing around the frame with nails (12).

Description

characterized in that it creates the metal deposit by electroplating.

  _ _ The present invention relates to a tensioning device

  automatic canvas on frame for oil painting.

  Currently the wooden frames used to support the canvases to paint with wind provided with keys, triangular wedges that are locked in notches made at each corner of the frame, which has the effect of spreading the sides so that

the canvas is stretched.

  This device has the drawback of being irreversible because once pressed the wedges cannot return to the rear, and if the fabric is too tight,

action cannot reduce its tension.

  By variation of the conditions of ambient temperature and humidity, the canvas retracts or expands, causing differences in tension which are detrimental to the good conservation of the paintings by the formation over time of cracks on the painted surface. On the other hand, an insufficient tension causes the canvas to float on its chassis, especially during transport, which is also a cause of degradation of the paintings. '! The device according to the invention enables these drawbacks to be remedied by the production of a spring system which 'pushes on a movable element of the chassis allowing the canvas to automatically tension in it.

imparting cons-tame tension.

  The COmpOrte device a fixed rectangular frame made of pine battens on which an external notch is

  practical to serve as a centering point for the mobile chassis.

  The battens wind assembled in sifú1et by gluing with dowel perpendicular to the cut, or any other mode

  assembly (mortise tenon for example).

  The mobile chassis is also rectangular and consists of

  pine battens ased in the same way as above.

  Its exterior dimensions are identical to those of the fixed chassis. Its interior dimensions are such that it can

  embed with play in the recess of the fixed frame.

  its upper face is chamfered towards the inside with a rounded u on the outside star in order to facilitate the sliding of the toilet

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  Leaf springs having a hole at one of their wind ends screwed into grooves made on the periphery of the lower frame. These grooves block the in-rotation springs. They have a length corresponding to the maximum elongation of the springs and their contact surface is as smooth as possible to ensure the free movement of the blades. With the same idea,

  these rear ends have their slightly raised free end.

  Alternatively, the leaf springs can be replaced by coil springs resting on each

  frame element in blind holes forming bowls.

  These latter can receive a metal washer to give a better seat to the springs. They have a depth such that in the fully compressed position of the I5 springs, the turns are partly covered, in order to limit the thickness of the assembly. O I1 there is sufficient clearance between the portour of the bowls and the springs

to avoid friction.

  To make the interlining, the two elements of the blackcurrant are kept close together using screws arranged on the bottom of the chassis. After the nailing of the canvas on the lower frame with seed type nails, the screws ..

Otees wind.

  The accompanying drawings illustrate the invention: FIG. I represents a top view of the lower chassis. FIG. 2 represents in section the section of a side of the lower chassis showing the notch and the

spring holder grooves.

  Figure 3 shows the top view of the entire

frame.

  The figure shows in section the section of a side of the

  chassis showing the mounting of leaf springs.

  Figure 5 repreesen-te endemi longitudinal section the position and shape of the springs- relaxed, without the

  representation of the upper chassis).

  Figure 6 shows a variant of this device, the top view of the entire chassis showing the layout

springs.

  Figure 7 is a cross-section of the spring installation

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  a sausage in the bowls, according to the same variant.

  Figure 8- shows in section the entire chassis in-

  interfacing position, in the case of leaf springs.

  With reference to these drawings, the device comprises a rectangular frame (I) of 550ormat 550 X 460 mm, consisting of battens of pine of section 40 X 20 mm in which is made a notch (3) of 20 mm wide X 10 mm height. Their assembly is in whistle with gluing and reinforcement by a wooden peg cur (2). 6 mm in diameter, adjusted perpendicular to the cut. Any other rigid assembly method can be considered. Grooves (9) of I40mm in length, I5mm in width and 3mm in depth are made in the grooves all over the periphery to receive the

  I5 leaf springs and hold them in the longitudinal position.

  These springs (8-) are made of steel blades of o, & mm thick have a hole of 3 mm at one end for their fixing by screws (IO). The other end which slides freely in the grooves on the surface of Portage isse, presents a rounded (I6), - and is slightly raised to

  avoid any snag and limit friction.

  The dis-pos-itif comprises a second rectangular chassis (4) of external dimension 550-X 10 mm, which comes to stencast with a total clearance of 4 to 5 mm in: 'notch of the chassis (I). It is made up of 22x18 mm section pine battens assembled according to the previous method. - Its upper face is chamfered (6) inward, forming an angle c (deIoq degree with the horizontal plane. The outer edge () has a rounded radius of 3 mm to facilitate the sliding of the toilet The leaf springs used have the following characteristics: Maximum compression length I35 mm. Width I3 mm. Relaxed height mm. Blade thickness 0, r8 mm. Compression force 6

KgP IO number.

  According to a variant of this arrangement, it is possible to use coil springs instead of leaf springs. These springs (I4) rest in basins (I3) with a diameter of I5 mm and a depth of 4 mm formed on each element of the chassis. You can place a metal washer (I5) of Imm thickness at the bottom of the cuvettes to ensure better

carrying springs.

  The coil springs used have the following characteristics: 0 I3 mm. 0 wire I, 3mm. Relaxed length 32 mm

  number of turns 7.Compression force 7 Kgf.

  To make the interlining, the springs (8) (I4) are compressed between the two elements of the chassis and held in this position by means of the screws (I7) screwed between the IO springs under the lower chassis. We can use greenhouse clamps to facilitate this operation. The canvas (II) is stretched by hand and nailed with seeds (I2) around the frame: (I} outIbis). Using a part

tender is not necessary.

  I5 Nailing "ermine, the screws (I7-) are removed, releasing the springs. Under the effect of the force exerted by all of the springs, the upper chassis moving away causes

  the tensioning of the fabric (II).

  Any variation in the condition of the canvas will be compensated by

  the action of the springs, hence a constant tension.

  The format of 550X460 mm (IO F) was taken as an assembly.

  This device can be applied to higher formats

  respecting the proportions of the different organs.

  The device according to the invention is particularly applicable

  to canvas to paint with oil paint.

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Claims (2)

CLAIMS I) Device for ensuring constant tension to the canvas to be painted on a wooden frame characterized in that it comprises two ChassS () and (4) superimposed and embedded with''Je. one in the other in a notch (3) practiced in the frame (I) ,. between which springs (8), or. (I4) according to a vari, ante, exert on all the periphery a bar which tends to move them apart and stiffening the fabric (II) retained by nailing on the frame (I) , or (Ibis) according to the variantz, 2d Dispositiú according to claim-I characterizes in that the two chassi's) and (4) 'd mmes - external dimensions are conti.tus cleats of pi'n ^ ass-emblds -from úago rigid e whistle by gluing and chevi'lles (2) and (5) e hard wood, adjusted perpendicular to the cut 3) Device according to claim I characterized in, that r-ainre $ (9) 'of lodgueur correspond to that of the springs, compressed, - are practical at the periphery of the frame (I) to receive with a lateral u.njeu the IO., springs.-leaf 4) Dis-positive according to claim I or 3 characterizes in that the spring blades- () are at one end drilled with a hole-for fixing them using the screws (Io): and have at the other end a slightly raised round (T 6 ) for F aciliter Ie - ,, sliding - $ ur..1a ;; sufac.p li, s ,, s.e, grooves ... ) Device according to claim I characterized in-cc that the frame (4), or (4bis) according to the variant, has its chamfered upper surface (6), terminated by a rounded (7) on its outer edge in order to facilitate the sliding of the canvas all around the frame. - 6 CLAIMS. 6) DispositiP according to claim I or claim 2 characterized in that the frames (Ibis) and (4bis-), depending on the variant, wind provided on their periphery with blind holes (I3) forming bowls to receive with a diametral clearance of coil springs (I4).   7) Device according to claim 6 characterized in that metal washers (I5) wind placed at the bottom of each bowl (I3) to ensure good   IO seated with IO coil springs (I4).   8) Device according to claim I characterized in that the wind frames kept close to each other using screws (I7) during the installation of the fabric (II).   I5 9) Dis-positive according to claim I or la.   claim (8) characterized in that the fabric (II) is nailed around the frame (I) or (Ibis), depending on the