Hand clamp

A hand clamp includes a housing having a handle for being held by a hand of a user, a piston rod slidably received in the housing, a driving lever engaged in the housing and having an opening for slidably receiving the piston rod and biased to grip the piston rod when the driving lever is tilted relative to the piston rod. A trigger is pivotally attached to the housing and has a driving shaft for tilting the driving lever to move the piston rod step by step. A braking lever is slidably engaged on the piston rod for gripping the piston rod when the braking lever is tilted relative to the piston rod. A hand grip is pivotally coupled to the handle and has an actuating end for actuating the braking lever to release the piston rod.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hand clamp, and more particularly to a hand clamp having an auxiliary hand grip for actuating and releasing a braking lever and for allowing the hand clamp to be easily operated with a single hand of a user.

2. Description of the Prior Art

Various kinds of typical hand clamps or C-clamps or clamping devices have been developed and comprise a piston rod slidably received in a grip body and including a jaw member movable toward and away from a fixed jaw that is solidly attached or coupled to the grip body for selectively grasping or gripping one or more work pieces between the jaw member and the fixed jaw.

For example, U.S. Pat. No. 5,217,213 to Lii discloses one of the typical quick release C-clamp including two pawls pivotally disposed in a grip and biased to engage with a rack that is slidably engaged in the grip. In operation, the user uses his one hand grasp the grip and actuate a handle to move the rack forwardly step by step. For releasing the rack from the pawls, the user has to use the other hand to rotate the rack relative to the handle and may not easily operate the C-clamp with one hand.

U.S. Pat. No. 6,648,315 to Lee discloses another typical clamping device including a catch plate and a release panel slidably engaged onto a piston rod and biased to be released and engaged onto the rod, a hand grip pivotally secured to a housing, and a pawl rotatably secured to the housing and engaged between the hand grip and the catch plate to tilt the catch plate relative to the piston rod, and a knob also rotatably secured to the housing and engaged between the hand grip and the release panel for releasing the release panel relative to the piston rod. However, the knob and the pawl may not be easily or effectively operated by the user.

The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional hand clamps or clamping devices.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a hand clamp including an auxiliary hand grip for actuating and releasing a braking lever and for allowing the hand clamp to be easily operated with a single hand of a user.

In accordance with one aspect of the invention, there is provided a hand clamp comprising a housing including a downwardly extending handle for being held by a hand of a user, and including a channel formed in the housing, a piston rod slidably received in the channel of the housing and movable forwardly and rearwardly relative to the housing, a driving lever engaged in the housing and including an opening for slidably receiving the piston rod when the driving lever is perpendicular to the piston rod, and for selectively engaging and gripping the piston rod when the driving lever is tilted relative to the piston rod, a first biasing device for biasing the driving lever relative to the housing and for forcing the driving lever to be perpendicular to the piston rod, a trigger pivotally attached to the housing, a driving shaft attached to the trigger and moved in concert with the trigger, for tilting the driving lever relative to the piston rod against the first biasing device, and for allowing the piston rod to be moved relative to the housing by the trigger and the driving shaft step by step when the trigger is cyclically pulled and released by the user, a braking lever engaged in the housing and including an opening for slidably receiving the piston rod when the braking lever is perpendicular to the piston rod, and for selectively engaging and gripping the piston rod when the braking lever is tilted relative to the piston rod, a second biasing device for biasing the braking lever relative to the housing and for forcing and tilting the braking lever to grip and brake the piston rod to the housing and to prevent the piston rod from sliding relative to the braking lever and the housing, and a hand grip pivotally coupled to the handle, and including an actuating end engage with the braking lever to selectively force and erect the braking lever against the second biasing device to a position perpendicular to the piston rod, and for selectively releasing the piston rod from the braking lever, the trigger and the hand grip being operatable with the hand of the user that hold the handle of the housing.

The housing includes a partition for separating a hollow interior of the housing into a rear chamber and a front chamber, the driving lever is received in the front chamber of the housing, and the braking lever is received in the rear chamber of the housing. The hand grip includes a lower end pivotally coupled to the handle with a pivot axle, and includes the actuating end provided on an upper portion and engaged into the rear chamber of the housing for engaging with the braking lever.

The handle includes a recess communicating with the rear chamber of the housing for receiving the hand grip and for allowing the actuating end of the hand grip to be extended and engaged into the rear chamber of the housing. The housing includes at least one side cap attached to one side of the housing for enclosing the rear and the front chambers of the housing.

The first biasing device includes a spring member received in the front chamber of the housing and engaged between the driving lever and the partition of the housing for biasing the driving lever relative to the housing. The second biasing device includes a spring member received in the rear chamber of the housing and engaged between the braking lever and the housing for biasing and tilting the braking lever relative to the housing.

The spring member of the second biasing device includes an opening for slidably receiving the piston rod. The spring member of the second biasing device includes an anchoring blade engaged with the housing and a biasing blade engaged with the braking lever.

The trigger includes a rounded upper end extended into the front chamber of the housing and pivotally engaged with the housing. The housing includes an upwardly extended fixed jaw for engaging with a work piece, and a gripping head attached to the fixed jaw for safely engaging with the work piece.

The piston rod includes a follower attached onto the piston rod, follower includes a groove for receiving the piston rod and includes an orifice communicating with the groove of the follower for receiving a fastener, the fastener detachably secures the follower to the piston rod. The piston rod includes a front hole and a rear hole for selectively engaging with the fastener.

A stop pin is selectively attached to either the front hole or the rear hole of the piston rod for engaging with the housing and for limiting the piston rod to slide relative to the housing and for preventing the piston rod from being disengaged from the housing. The follower includes a jaw member for engaging with a work piece, and a gripping head attached to the jaw member for safely engaging with the work piece.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, and initially toFIGS. 1–4, a hand clamp10in accordance with the present invention comprises a grip body or housing11including a handle12extended downwardly therefrom for being held or grasped by the user, and a fixed jaw13extended from the housing11, such as extended upwardly from the housing11for contacting or engaging with a work piece90(FIGS. 4,6,9), it is preferable that a soft or resilient gripping head14is attached to the fixed jaw13for softly or resiliently and safely contacting or engaging with the work piece90.

The housing11includes a hollow interior, and a partition15disposed or engaged in the hollow interior of the housing11for separating the hollow interior of the housing11into two chambers16,17, such as a rear chamber16and a front chamber17. The housing11includes a longitudinal channel18formed therein and formed through the partition15and communicating with the rear and the front chambers16,17thereof for slidably receiving a piston rod20therein, and for allowing the piston rod20to be moved forwardly and rearwardly relative to the housing11. One or two side caps19may be attached to either or both of the sides of the housing11for enclosing the chambers16,17of the housing11.

The piston rod20includes a front hole21and a rear hole22formed therein for selectively attaching or securing a follower23. For example, the follower23includes a groove24formed therein for receiving either of the ends of the piston rod20, and includes an orifice25laterally formed therein and communicating with the groove24of the follower23for receiving a fastener26which may be threaded to either of the front hole21or the rear hole22of the piston rod20and to detachably secure the follower23to either of the ends of the piston rod20.

The follower23includes a jaw member27extended therefrom, such as extended upwardly from the follower23for contacting or engaging with the work piece90(FIGS. 4,6,9), it is also preferable that a soft or resilient gripping head28is attached to the jaw member27for softly or resiliently and safely contacting or engaging with the work piece90. The jaw member27is movable together with the piston rod20for being moved toward or away from the fixed jaw13and for clamping the work piece90between the fixed jaw13and the jaw member27(FIGS. 4,6) or for forcing the fixed jaw13and the jaw member27onto the work pieces90(FIG. 9).

A stop pin29may be selectively attached or engaged into either of the front hole21or the rear hole22of the piston rod20, as shown inFIGS. 3,4,6and9, for engaging with the housing11and for limiting the piston rod20to slide relative to the housing11and for preventing the piston rod20from being disengaged from the housing11. As described above, the follower23may be attached to either the front portion of the piston rod20(FIGS. 2–4,6) or the rear portion of the piston rod20(FIGS. 8–9), and the stop pin29may thus be selectively attached to the rear portion or the front portion of the piston rod20.

A trigger30includes an aperture31formed in the middle or upper portion thereof for receiving a driving shaft32which is received in the front chamber17of the housing11(FIGS. 3,4,6), and includes a rounded upper end33extended into the front chamber17of the housing11and pivotally engaged with the housing11for pivotally or rotatably securing or attaching the trigger30to the housing11, and for allowing the driving shaft32to be moved in concert with the trigger and to be moved forwardly and rearwardly relative to the housing11by the trigger30(FIGS. 3,4,6).

A driving lever40is received or engaged in the front chamber17of the housing11and includes an opening41, such as a rectangular opening41formed therein and arranged for slidably receiving the piston rod20when the driving lever40is disposed perpendicular to the piston rod20(FIGS. 3,6), and for selectively engaging or gripping the piston rod20when the driving lever40is tilted or slanted relative to the piston rod20(FIGS. 4,5), and thus for allowing the piston rod20to be moved relative to the housing11by the trigger30and the driving shaft32step by step when the trigger30is cyclically pulled and released by the user.

A spring biasing means or member42is also received or engaged in the front chamber17of the housing11and disposed or engaged between the driving lever40and the partition15of the housing11for biasing or erecting the driving lever40relative to the partition15and for forcing the driving lever40to be arranged perpendicular to the piston rod20(FIGS. 3,6), and thus for allowing the piston rod20to slide or to move relative to the driving lever40. In operation, the piston rod20may be moved relative to the housing11step by step by moving the driving shaft32against the spring member42with the trigger30, and the spring member42may then bias and erect the driving lever40relative to the partition15when the trigger30is released.

A braking lever50is received or engaged in the rear chamber16of the housing11and includes an opening51, such as a rectangular opening51formed therein and arranged for slidably receiving the piston rod20when the braking lever50is disposed perpendicular to the piston rod20, and for selectively engaging or gripping the piston rod20when the braking lever50is tilted or slanted relative to the piston rod20(FIGS. 3,4,6–7), and thus for allowing the piston rod20to be gripped or braked or anchored to the housing11when the braking lever50is tilted or slanted relative to the piston rod20.

A spring biasing means or member60is also received or engaged in the rear chamber16of the housing11and includes an opening61, such as a rectangular opening61formed therein for slidably receiving the piston rod20, and the spring member60is disposed or engaged between the braking lever50and the housing11for biasing or tilting or slanting the braking lever50relative to the housing11and the piston rod20, and for forcing the braking lever50to grip and brake and anchor the piston rod20to the housing11and to prevent the piston rod20from sliding or moving relative to the braking lever50and the housing11. For example, as shown inFIGS. 1 and 7, the spring member60includes an anchoring blade62biased and engaged with the housing11, and a biasing blade63engaged with the braking lever50for normally biasing or tilting or slanting the braking lever50relative to the housing11.

A hand grip80includes one end or lower end rotatably or pivotally coupled or secured to the housing11or the handle12with a pivot axle81, for example, the housing11or the handle12includes a recess82formed therein (FIG. 1) for receiving the hand grip80, and the recess82of the housing11or the handle12is communicating with the rear chamber16of the housing11for allowing another end or an upper actuating end83of the hand grip80to be provided for directly or indirectly actuating the braking lever50, best shown inFIGS. 6 and 7, and to selectively erect the braking lever50to a position perpendicular to the piston rod20against the spring member60. For example, the upper actuating end83of the hand grip80may be directly engaged with the braking lever50for selectively moving or erecting the braking lever50against the spring member60.

Alternatively, as shown inFIGS. 1,3,6and7, an actuator85may further be provided and rotatably or pivotally attached or coupled to the housing11with a pivot pole86for allowing the actuator85to be rotated relative to the housing11and for allowing the actuator85to be moved to engage with the braking lever50. For example, the actuator85may include the upper end pivotally attached or coupled to the housing11with the pivot pole86, and may include a lower end87for engaging with the actuating end83of the hand grip80(FIGS. 3,4,6) and for allowing the actuating end83of the hand grip80to engage with or to actuate the actuator85to operate or to actuate the braking lever50. For example, the housing11may include a curved recess88for rotatably or pivotally receiving and retaining the pivot pole86.

In operation, as shown inFIGS. 3,4,6–7, the spring member60may bias or tilt or slant the braking lever50relative to the housing11and the piston rod20to force the braking lever50to grip and brake and anchor the piston rod20to the housing11and to prevent the piston rod20from sliding or moving backwardly relative to the braking lever50and the housing11. The piston rod20may then be moved forwardly relative to the housing11by the trigger30and the driving shaft32step by step when the trigger30is cyclically pulled and released by the user.

When it is required to release the piston rod20from the housing11, it is only required to depress or actuate the hand grip80in order to actuate or to force the actuating end83of the hand grip80to engage with the actuator85and to indirectly actuate the braking lever50via the actuator85(FIG. 7), and to selectively erect the braking lever50to a position perpendicular to the piston rod20and thus to allow the piston rod20to slide relative to the housing11and the braking lever50. When the hand grip80is released by the user, the spring member60may bias or tilt or slant the braking lever50relative to the housing11and the piston rod20to force the braking lever50to grip and brake and anchor the piston rod20to the housing11again, and to prevent the piston rod20from sliding or moving relative to the braking lever50and the housing11again.

It is to be noted that the user may use his one hand to hold the handle12, and use his four fingers to pull or actuate the trigger30, and may then use one of his four fingers of the hand that holds the handle12to pull or actuate the hand grip80to force the actuating end83of the hand grip80to directly actuate the braking lever50or to indirectly actuate the braking lever50via the actuator85, such that the hand clamp10may be easily operated with a single hand of the user.

Accordingly, the hand clamp in accordance with the present invention includes an auxiliary hand grip for actuating and releasing the braking lever and for allowing the hand clamp to be easily operated with a single hand of the user.