The invention relates to corner clamps, and more particularly to a corner clamp for woodworking.
When boards (e.g. planks) are assembled to form frames (e.g. wood frames), in order to facilitate fixing (e.g. screw fixing) of the corner where the ends of the boards meet, corner clamps are used for temporarily clamping the connected corner of the boards.
A conventional corner clamp is used for clamping and securing the connected corner of boards temporarily, but the clamping force relies on the rebound force of a compression spring. As a result, when the connected boards are impacted by an external force before the boards are locked, because the chuck has no retreat restriction or has no locking function after the chuck clamps the boards, it is easy for the connecting ends of the boards to deviate or shift due to excessive external force.
The primary object of the invention is to provide a corner clamp for woodworking. The corner clamp comprises a clamp body, a slider, a chuck, at least one detent, an eccentric pull member, and a slider spring.
The clamp body has a carrying seat. An upper surface of the carrying seat has a slide surface. An elongate guide hole is formed on the slide surface. At least one of both sides of the elongate guide hole is formed with an anti-slip portion on the slide surface. Two sides of one end of the carrying seat are enlarged and have a pair of resting blocks. The other end of the carrying seat extends downward to form a support portion. The pair of resting blocks each have a resting surface on an inner surface thereof. An included angle of 60 degrees to 150 degrees is defined between the resting surfaces of the pair of resting blocks.
The slider has a frame-shaped base that is slidable on the slide surface. The bottom of the frame-shaped base is formed with a guide block that matches the elongate guide hole and is engaged with the bottom edge of the wall of the elongate guide hole. The frame-shaped base has a press portion that is located below the carrying seat and faces the support portion. The frame-shaped base further has a pair of pivot portions and an accommodating room between the pair of pivot portions. A receiving portion is provided on the bottom of at least one of two sides of the accommodating room adjacent to the pivot portions. The receiving portion is formed with a through hole relative to the anti-slip portion.
The chuck is disposed at one end of the frame-shaped base opposite the accommodating room. The chuck has a head. Two sides of the head are respectively formed with clamping surfaces relative to the resting surfaces of the pair of resting blocks. The clamping surfaces are parallel to the resting surfaces.
The detent is disposed on the receiving portion. The detent has a detent body that is movable in the through hole. The bottom of the detent body is formed with a locking surface relative to the anti-slip portion.
The eccentric pull member has a rotating member pivoted to the pair of pivot portions with a pivot rod. An operating portion is formed on one side of the rotating member. At least one of both ends of the eccentric pull member is formed with a first eccentric portion relative to an upper surface of the detent body of the detent. The first eccentric portion is configured to press the detent body to move in the through hole and enables the locking surface to be in tight contact with the anti-slip portion.
One end of the slider spring is pressed against the support portion of the clamp body, and the other end of the slider spring is pressed against the press portion of the slider for pushing the clamping surfaces of the chuck to lean against the resting surfaces of the pair of resting blocks normally.
When the corner clamp is to be used at the corner where the ends of the two boards meet, the chuck on the slider is operated to slide away from the pair of resting blocks of the clamp body, such that a pair of clamping openings for the two boards to be inserted are formed between the chuck and the pair of resting blocks. When the two boards are inserted in the pair of clamping openings, the slider is pushed back by the press portion using the rebound force released by the compression of the slider spring after the slider is slid, so that the resting surfaces of the pair of resting blocks and the clamping surfaces on both sides of the head of the chuck together clamp the two boards. The operating portion of the eccentric pull member pulls the first eccentric portion toward the chuck to press the detent body of the detent. The non-slip effect generated by the locking surface of the bottom of the detent body to be in tight contact with the non-slip surface restricts the slider from sliding on the slide surface of the clamp body. Thus, the resting surfaces of the pair of resting blocks and the clamping surfaces of the chuck work together to clamp the two boards, so as to achieve the effect of preventing loosening when the ends of the two boards are connected and temporarily clamped.
Preferably, the clamp body further has a notch at the position where the elongate guide hole meets the support portion. A pair of engaging gaps are formed at the junction of the notch and the wall of the elongated guide hole. Two sides of the bottom of the guide block of the slider are formed with a pair of engaging portions relative to the engaging gaps. For assembly, the slider is turned, with the press portion being parallel to the elongate guide hole, and then the press portion is inserted and swiveled after passing through the elongate guide hole. The guide block is inserted and moved forward toward the notch. The engaging portions are engaged with the bottom edge of the wall of the elongate guide hole via the engaging gaps, so that the slider can be easily and slidably connected to the carrying seat of the clamp body.
Preferably, the press portion of the slider is formed with a neck corresponding in width to the elongate guide hole of the clamp body. The slider can assist the guide block to be positioned in the elongate guide hole via the neck to jointly generate displacement guidance, so as to reduce or avoid the slide offset phenomenon when the slider slides on the slide surface of the carrying seat.
Preferably, the included angle between the resting surfaces of the pair of resting blocks of the clamp body is 90 degrees. When the ends of the two boards meet vertically, the corner clamp is used for clamping and securing the two boards at the vertically connected corner of the two boards.
Preferably, a curved groove is formed on the receiving portion of the slider. The curved groove is provided with a resilient member at a position separated from the through hole. One end of the detent body of the detent has a pivotal portion mounted on the curved groove for swinging. The other end of the detent body of the detent has a push portion that rests on the elastic member. The elastic member pushes the push portion so that the locking surface is normally away from the anti-slip portion on the slide surface of the clamp body. When the eccentric pull member is pulled toward the chuck, the first eccentric portion presses the detent body of the detent to swing downward, such that the locking surface is in tight contact with the stop-slip portion, and the slider won't slide on the slide surface. On the contrary, when the eccentric pull member is pulled back, the resilient force of the elastic member pushes back the locking surface of the detent away from the anti-slip portion, thereby releasing the sliding restriction of the slider on the slide surface. The non-slip portion on the slide surface of the clamp body is a toothed surface having a plurality of teeth arranged in parallel. The locking surface of the detent is a toothed surface having teeth corresponding in shape and in space width to the teeth of the anti-slip portion. When the locking surface is in tight contact with the anti-slip portion, the teeth of the locking surface mesh with part of the teeth of the anti-slip portion, so as to enhance the non-slip capability of the slider on the slide surface.
Preferably, anti-slip soft rubber pads are provided on the resting surfaces of the resting blocks at one end of the carrying seat of the clamp body and the clamping surfaces on the two sides of the head of the chuck, respectively. Outer surfaces of the anti-slip soft rubber pads are defined as the resting surfaces and the clamping surfaces. The damping and anti-slip properties of the anti-slip soft rubber pads, increase the ability to stop slippage when the resting surfaces of the pair of the resting blocks and the clamping surfaces of the chuck work together to clamp or lock the boards.
Preferably, a protrusion and a recess are provided on the support portion of the clamp body and the press portion of the slider for mounting the slider spring. The protrusion and the recess are interchangeable with each other. When one end of the slider spring is pressed against the support portion and the other end of the slider spring is pressed against the press portion, the protrusion and the recess restrict the radial retraction of the slider spring. The stability of the slider spring is increased when the press portion is moved close to or away from the support portion.
Preferably, the end of the frame-shaped base of the slider, opposite to the accommodating room, forms a platform portion that is separated by a retaining wall. The retaining wall has a doorway that allows the platform portion to communicate with the accommodating room. A guide part is provided on a surface of the platform portion corresponding to the doorway. The chuck has an extension section extending from one end of the head. The extension section is placed on the surface of the platform portion and inserted into the accommodating room via the doorway. The guide part is accommodated in the extension section, so that the chuck is guided by the guide part, enabling the head of the chuck to move close to/or away from the retaining wall on the platform portion. A chunk spring is provided in the extension section. One end of the chuck spring is pressed against the guide part, and the other end of the chuck spring is pressed against an inner surface of the extension section, thereby pushing the head to approach the retaining wall normally. A second eccentric portion is provided on one side of the rotating member of the eccentric pull member. The second eccentric portion is normally away from one end face of the extension section. After the eccentric pull member is pulled toward the chuck, the second eccentric portion is pushed against the end face of the extension section. When the pair of resting blocks and the chuck work together to clamp the boards, the eccentric pull member is pulled toward the chuck, such that the first eccentric portion presses the detent to restrict the slider from sliding on the slide surface, and the second eccentric portion pushes against the end face of the extension section of the chuck, causing the chuck to generate forward movement energy. Thus, the clamping surfaces of the chuck form a tightening effect on the surfaces of the boards, thereby increasing the stability of the corner clamp to clamp the boards.
and
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings.
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The clamp body 20 has a carrying seat 21. An upper surface of the carrying seat 21 has a slide surface 22. An elongate guide hole 23 is formed on the slide surface 22. At least one of both sides of the elongate guide hole 23 is formed with an anti-slip portion 24 on the slide surface 22. As shown in the figures, a pair of anti-slip portions 24 are formed on both sides of the elongate guide hole 23. Two ends of one end of the carrying seat 21 are enlarged and have a pair of resting blocks 25. The other end of the carrying seat 21 extends downward to form a support portion 26. The pair of resting blocks 25 each have a resting surface 250 on an inner surface thereof. An included angle α of 60 degrees to 150 degrees is defined between the resting surfaces 250 of the pair of resting blocks 25.
The slider 30 has a frame-shaped base 31 that is slidable on the slide surface 22. The bottom of the frame-shaped base 31 is formed with a guide block 32 that matches the elongate guide hole 23 and is engaged with the bottom edge of the wall of the elongate guide hole 23. The frame-shaped base 31 has a press portion 33 that is located below the carrying seat 21 and faces the support portion 26. The frame-shaped base 31 further has a pair of pivot portions 34 and an accommodating room 35 between the pair of pivot portions 34. A receiving portion 36 is provided on the bottom of at least one of two sides of the accommodating room 35 adjacent to the pivot portions 34. As shown in the figures, the receiving portion 36 is provided at the bottom of either side of accommodating room 35. The receiving portion 36 is formed with a through hole 37 relative to the anti-slip portion 24.
The chuck 40 is disposed at one end of the frame-shaped base 31 opposite the accommodating room 35. The chuck 40 has a head 41. Two sides of the head 41 are respectively formed with clamping surfaces 410 relative to the resting surfaces 250 of the pair of resting blocks 25. The clamping surfaces 410 are parallel to the resting surfaces 250.
The detent 50 is disposed on the receiving portion 36. As shown in the figures, two detents 50 are disposed on the receiving portions 36, respectively. The detent 50 has a detent body 51 that is movable in the through hole 37. The bottom of the detent body 51 is formed with a locking surface 52 relative to the anti-slip portion 24.
The eccentric pull member 60 has a rotating member 62 pivoted to the pair of pivot portions 34 with a pivot rod 61. An operating portion 63 is formed on one side of the rotating member 62. At least one of both ends of the eccentric pull member 60 is formed with a first eccentric portion 64 relative to an upper surface of the detent body 51 of the detent 50. The first eccentric portion corresponds in number and in position to the detent. As shown in the figures, a pair of first eccentric portions 64 are provided on two ends of the eccentric pull member 60. The first eccentric portion 64 presses the detent body 51 to move in the through hole 37 and enables the locking surface 52 to be in tight contact with the anti-slip portion 24.
One end of the slider spring 70 is pressed against the support portion 26 of the clamp body 20, and the other end of the slider spring 70 is pressed against the press portion 33 of the slider 30 for pushing the clamping surfaces 410 of the chuck 40 to lean against the resting surfaces 250 of the pair of resting blocks 25 normally.
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Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.