A structure of a hacksaw includes a frame which is combined by a fore part and a rear part, an adjustable mechanism under the fore part connected to one end of the blade for adjusting the tilt angle of the blade, a positioning mechanism under the rear part connected to the other end of the blade and for tensioning the blade by a wedge lever. The frame disassembly to quickly adjust the length to serve different lengths of the blade.

A hacksaw of the type utilizing an elongated blade maintained tension between respective legs of the saw frame includes a cam-actuated blade tensioning mechanism. One leg of the saw frame includes a fixed blade pin for receipt through a mounting hole defined at one end of the elongated blade. The other leg of the saw frame includes a pin carrier having a blade pin for receipt through the mounting hole defined at the other end of the elongated blade. The pin carrier is pivotal between a blade release position and a blade securement position. In presently preferred embodiments, the pin carrier defines a cam follower engaging an elliptically arcuate cam surface defined on a pivotal actuator member. The actuator member may have a lever portion for providing mechanical advantage during its pivotal movement. A releasable lock mechanism is provided to maintain the actuator member, and thus the pin carrier, in the blade securement position during use. Preferably, the releasable lock mechanism is configured to require the simultaneous occurrence of two events in order to permit release of the blade.

A hacksaw includes a blade tensioning mechanism attached to the lower portion of the handle and connected to the blade through a blade holder. The end of the blade holder is observed via a tension indicator window at the lower portion of the handle, and the handle has respective predetermined indicia adjacent to the tension indicator window for alignment with the end of the blade holder. The blade tension mechanism includes an adjusting screw threadingly engaging the blade holder, and a crank handle mechanically engaging the adjusting screw for adjusting the tension of the blade. At the desired blade tensioning, the crank handle is mechanically disconnected from the adjusting screw and fits closely in the recess underneath the lower portion of the handle.

A low profile hacksaw comprising an elongated blade having a cutting edge. A rigid I-beam frame member has a forward end portion and a maximum height portion. Preferably, the maximum height portion is located at the rear end of the frame member, but it may be located intermediate the forward and rearward ends. The frame member has an arcuate portion which extends substantially the entire length between the forward end and maximum height portions and which curves downwardly and forwardly towards the forward end portion to provide the hacksaw with a low profile. A manually engageable handle is provided for manual grasping to enable performance of a cutting operation wherein the cutting edge of the tensioned blade is engaged with a work piece and moved forwardly and rearwardly to cut through the work piece. A releasable blade tensioning device provides a second blade mounting structure on which the other longitudinal end portion of the blade is removably mounted. The blade tensioning device is constructed and arranged to affect relative movement between the first and second blade mounting structures to tension the blade in the longitudinal direction thereof and thereby apply a rearwardly directed force to the forward end portion of the frame member. As a result, the rearwardly directed load applied to the forward end portion creates a bending moment which is distributed throughout and resisted by the frame member as a result of its curvature and I-beam configuration.

The present invention relates to hacksaws. One aspect of the invention relates to a hacksaw with an overmolded frame member wherein the overmolded material has an I-beam configuration. Another aspect of the invention relates to an improved blade tensioning device that reduces the tension load borne by the tensioning device's mounting structure. Another aspect of the invention relates to a method for cutting metal frame members with a reduced amount of scrap.