JP7682225B2 - Canvas stretcher - Google Patents

Description

This relates to an instrument used when stretching canvas cloth (hereinafter referred to as canvas) onto the surface of a canvas board.

Conventionally, when stretching a canvas on a canvas board having a wooden frame, the common method has been to grip the edge of the canvas with pliers and pull it using a lever while fastening it to the frame with nails or staplers.
A canvas stretcher using turnbuckles is also known (see Patent Document 1).
Also known is a canvas tensioner that utilizes a hand vice (see Patent Document 2).
Ratchet mechanisms have been used in various forms in tightening devices such as packing straps.

Jitszen No. 57-53400 Publication Jitszen Showa 63-112100 Publication

The prior art shown in Patent Document 1 has a reciprocal reverse thread hook on both ends of a long, thin metal body (turnbuckle), and while rotating the body, the clips holding both ends of the canvas are pulled toward the center to tighten the tension, and then rotated in the opposite direction to loosen and remove the canvas. However, it is not possible to loosen or remove the canvas unless the turnbuckle is rotated in the opposite direction the number of turns required for pulling and tightening. In addition, there is a concern that the holding force of the clips on both ends is not very strong. In this series of operations, the turnbuckle must be kept floating off the board throughout the entire operation in order to rotate it by hand, and it continues to swing unstably in the air, and irregular, unstable, and uneven forces are constantly applied to both ends of the stretched canvas. From experience, it is difficult to complete the stretching process neatly and efficiently in a pleasant manner.
In the prior art shown in Patent Document 2, the weight of the hand vice is extremely heavy, which is inconvenient for women in particular. In addition, even if the edge of the canvas is firmly grasped, the important thing in stretching the canvas is how to stabilize it horizontally and vertically without any shaking, and how to pull and tighten the canvas with the appropriate amount of force to settle it at the most suitable tension, but the key point is unclear and it is left to the user's discretion. Here, as in the above-mentioned Document 1, the entire process of operating the tool must be carried out in the air, and since the tool is much heavier than the turnbuckle, the irregularity, instability, and unevenness of the force applied to the canvas are all the more noticeable. This is a very worrying stress for those who want to start creating a painting quickly.
The present invention provides a tool that can be used by anyone, male or female, and allows the artist to quickly determine the tension and stability that feels comfortable to them in as few steps as possible, and once the work of fixing the canvas is complete, eliminates the tedious and laborious reproduction process of having to go back the way you came, and instead provides a tool that allows the artist to quickly loosen the clips that have been tightly gripping the canvas with a small twist, releasing the canvas and allowing the device to be removed.

This is a tool used to precisely position the canvas on the canvas board (hereinafter referred to as the board) vertically and horizontally.
A main body having a ratchet mechanism (hereinafter referred to as a ratchet portion);
A canvas gripping clip is used to firmly grip the canvas that has been folded over from the front to the back via the wooden frame of the board, i.e., the board frame, pulling it from the opposing vertical and horizontal edge frames to the center of the back of the board to tighten it.
It is composed of two major elements:
For ease of explanation, the shape of the main body will be likened to a stapler type, and the part corresponding to the handle where the needles are set in a stapler will be referred to as the lever part, and the part corresponding to the arm against which the needles are pressed will be referred to as the leg part.
The main body is provided with a ratchet section at the starting area where the lever section and the leg section are bifurcated,
At the lever,
It has a groove-shaped recessed space on the back side when viewed from the leg, and the upper edge of the groove wall slides to cover the recessed space, and is connected to a coil spring fixed to a portion of the groove near the ratchet portion, and is provided with a neutral lever that is detachably clipped to the other end of the groove, i.e., the end portion of the lever portion.
In the legs,
A canvas gripping clip is provided at the end of the tension belt which is rolled up around the rotating shaft of the ratchet section and extends outward (opposite the leg section), and a spring-type tension relief section is provided at the end of the leg section which extends in the opposite direction, and a canvas gripping clip is provided at the end of the tension relief section;
Both of these canvas clips are closed at one end (the end facing the legs) and open at the other end (the end facing the canvas) in two pieces, one above and one below. In the centre of the opening there is a spring which expands and contracts up and down, and a thumbscrew is attached to the outside of the upper piece, allowing the gripping strength of the opening which holds the canvas to be freely adjusted.
Unless there are some very special circumstances, when adjusting the canvas tension, you can restart the work by simply twisting the thumbscrew, without having to go through the trouble of neutralizing the ratchet function, relaxing the tension belt, and turning the lever back.
Thus, while the conventional ratchet mechanism and the associated neutralization mechanism are applied to the work procedures specific to canvas stretching, the desired tension can be quickly achieved while maintaining stability in the tensioning work, and the process of fixing a taut canvas to the frame can be completed in one go with almost no hassle, without the need to turn the lever back to its original position via the neutral lever operation, allowing you to focus on creating a painting in a comfortable atmosphere.
This is a canvas stretcher having the above features.

(i) The tool can be held away from the hands and placed with its legs in contact with the board surface, like the legs of a person sitting on a seat. This means that the user is freed from the weight of the tool and the instability of operation when stretching a canvas, and the desired tension can be achieved reliably and quickly.
(b) With conventional devices, the degree of tension of the canvas that felt appropriate when held in the hand was inevitably subject to slight errors once the canvas was removed from the hand. With this device, however, the canvas can be fixed to the stretcher at the level that feels optimal.
(c) Whether you need to redo an adjustment or have completed the desired tensioning, you can enjoy the unique advantage of the ratchet mechanism, which is that it irreversibly turns the ratchet wheel one pawl at a time in only one direction, without being bothered by the negative advantage that comes with it (you cannot go back one pawl at a time).With a single twist of the thumbscrew, you can start redoing the adjustment or remove the canvas in an instant.
(ii) It can be used by anyone, regardless of the difference in muscle strength between men and women, or by people who get frustrated easily with fine adjustments or redoing tasks.
(e) The structure is simple and clear, and regardless of dexterity or clumsiness, the desired results can be achieved in a short amount of time, allowing one to move on to creating something.

FIG. 1 is a perspective view of the exterior of the present invention; A side view of the canvas gripping clip that is part of the present invention. 3 is a cross-sectional view of the canvas gripping clip shown in FIG. FIG. 1 is a perspective view of the appearance of the present invention in a used state.

The following describes the embodiment and usage of the present invention.
This is a tool used to neatly stretch and set a canvas on a canvas board for painting, and it consists of a main body (1) equipped with a ratchet part (5);
This method is composed of two major elements: canvas gripping clips (2) that firmly grip the canvas (S), which is folded from the front to the back of the board (B) via the board frame (F), in order to pull and taut it from the opposing board frames (F) vertically and horizontally to the center of the back of the board (B).
The main body (1) is split into two parts, a lever part (3) and a leg part (4), starting from the ratchet part (5), and has a shape resembling a sideways V.
In the lever portion (3),
It has a groove-shaped recessed space on the back side when viewed from the leg portion (4), and is equipped with a neutral lever (10) that slides along the upper edge of the groove wall in a manner that covers the recessed space, is connected to a coil spring (11) fixed to a portion of the groove near the ratchet portion (5), and forms a detachable fixed portion (12) that is detachably clipped on the other end side of the groove, i.e., the terminal portion of the lever portion (3).
In the leg (4),
A canvas gripping clip (2a) is provided at the end of the tension belt (6) which is rolled up around the rotating shaft of the ratchet section (5) and extends outward (opposite the leg section), a spring-type tension relief section (7) is provided at the end of the leg section which extends in the opposite direction, and a canvas gripping clip (2b) is provided at the end of the tension relief section (7).
Both of these canvas gripping clips (2) are closed at one end (the side facing the leg) and have two openings, one above and one below, at the other end (the side facing the canvas). In the center of the opening is an opening/closing spring (8) that expands and contracts vertically, and a thumbscrew (9) is provided on the outside of the upper piece, allowing the gripping strength of the opening that grips the canvas (S) to be freely adjusted.
The present invention has the above-mentioned configuration, and its usage will be explained below.
When using this, the canvas is placed under the board and the frame, folded back through the vertical (or horizontal) opposing board frame, the present invention is placed on the board surface in the middle of the opposing two sides, the canvas holding clip (2a) and the canvas holding clip (2b) hold both ends of the canvas (S) at the point where they are almost parallel to the horizontal (or vertical) board frame (F), the thumbscrew (9) is quickly tightened to fix it, and the lever part (3) is rotated one step at a time with a ratchet to pull the canvas (S) from both ends toward the center and tighten it. Even if the canvas becomes a little too tight during this process, the excessive tension is naturally relaxed by the automatic spring adjustment of the tension relief part (7). When the appropriate tension is achieved, the canvas is fixed to the frame (F) in that state with a nail or stapler.
This operation is repeated several times, shifting the position of the edge of the canvas (S) that is gripped by the canvas gripping clip (2). Conventionally, the tool must be removed from the canvas (S) each time, and this has been a problem due to the negative advantage of the ratchet mechanism (irreversible rotation in only one direction). However, with the use of this invention, the tool can be removed from the canvas (S) with a single twist of the thumbscrew (9), so the work point can be moved to the next position immediately. In this way, once the canvas (S) has been secured to the vertical board frame (F), the same procedure can be used to quickly secure the canvas (S) to the horizontal board frame (F). Previously, this was the most tedious and tedious procedure that artists had to go through because there was no other way, but now, with just one quick touch, this is a blessing for artists who want to get down to creative work in a good mood; it cannot be described as simply "reducing preparation time."

Reference Signs List 1 Main body 2 Canvas gripping clip 2a Canvas gripping clip 2b Canvas gripping clip 3 Lever section 4 Leg section 5 Ratchet section 6 Tension belt 7 Tension relief section 8 Opening/closing spring 9 Thumb screw 10 Neutral lever 11 Coil spring 12 Detachable fixing section B Board F Board frame S Canvas

Claims (3)

A stretching tool used to stretch a canvas onto a canvas board,
A main body having a lever part and a leg part each having a neutral lever, the lever part and the leg part being bifurcated from a ratchet part as a starting point;
The whole body is placed on the board surface via the legs, which grip the canvas and pull it towards the body to tighten it.
A canvas stretcher comprising: In the legs,
A canvas stretcher as described in claim 1, characterized in that at one end, it has a canvas gripping clip at the end of the tensioning belt that is rolled up around the rotating shaft of the ratchet section and extends outward (towards the canvas on the side opposite the leg section), and at the other end, it has a spring-type tension relief section and another identical canvas gripping clip at the end of the tension relief section. On two canvas clips,
Both are closed at one end (opposite the legs) and open at the top and bottom at the other end (opposite the canvas).
A spring that expands and contracts vertically is installed in the center of the opening, and a thumbscrew is installed on the outside of the upper piece, allowing the strength with which the opening grips the canvas to be freely adjusted.
2. A canvas stretcher as claimed in claim 1, characterized in that:

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