Patent Application
20100275740
The present invention relates to a retaining mechanism according to the preamble of claim 1.
Handheld tools such as crimping tools are often equipped with a pawl and ratchet mechanism, the main object of which is to assure that an intended working cycle is completed. An accompanying advantage with these pawl and ratchet mechanisms is that they make it possible to maintain the handles in a squeezed together condition when the grip is released. There are a number of previously known technical solutions for achieving this, but they are often quite complicated. This adds to the manufacturing cost and also the assembly costs.
Another drawback with tools in the market is that in order to loosen the grip of the tool, the handles must be squeezed together into a predetermined relative position corresponding to a completed working cycle, whereupon the retaining mechanism will be released.
Accordingly, there is a need of an improved retaining mechanism.
The object of the invention is to provide an improved retaining mechanism for two pivotally fixed handles of a handheld tool with which the drawbacks of prior art devices are mitigated.
This and other objects are achieved with the retaining mechanism as defined in claim 1. Preferred embodiments and developments of the invention are defined in the dependent claims.
The invention will now be described more in detail in connection with a preferred embodiment of the invention with reference to the accompanying drawing, in which
The retaining mechanism according to the invention is designed to be used with handheld tools such as pliers of different kinds, and especially with crimping tools, having two handles being pivotally connected to each other.
In
The retaining mechanism according to the invention thus comprises said two handle element parts 1 and 2, and a pawl and ratchet arrangement acting between said element parts.
On the first handle element part 1 is arranged a first arm 4 carrying a rack of teeth 5 extending over part of said arm, leaving an empty space between said first handle element part 1 and said rack of teeth. On the second handle element part 2 is arranged a pawl 6 mounted on or being an integral part of a second arm 7. Accordingly, the pawl and the second arm are in fact one and the same element, which is an important improvement in view of prior art devices.
The first arm 4 carrying the rack of teeth is preferably curved corresponding to the swivelling motion of the handle element parts around the pivot pin 3.
In a preferred embodiment, as shown in
On the end of the first arm 4 is arranged a first guide surface 8 sloping upwards towards the rack of teeth. The end of the second arm 7 is formed with a corresponding second guide surface 9 pointing upwards.
Said arms are arranged on said handle element parts with their longitudinal axes parallel to each other and offset so that when said handle element parts are squeezed together they will move adjacent to each other. The pawl extends laterally from the flexible arm so that it will slide up onto the rack of teeth, and when the handle element parts are squeezed together the pawl will jump over the rack of teeth one by one, and when the squeezing force is released the pawl will be arrested on one of the teeth.
At least one of said first and second arms 4, 7 is flexible. In a preferred embodiment, which is illustrated on the drawing, the second arm incorporating the pawl 6 is flexible.
However, in the mechanism according to the invention the arm carrying the rack of teeth could be the flexible arm, or both arms could be flexible.
When the flexible arm is bent and the pawl is guided up onto the rack of teeth it will exert an elastic force and the pawl will be biased against the teeth with a sufficient pressure to keep the pawl in contact with the rack of teeth.
At the inner end of said rack of teeth, a third guide surface 10 is arranged. When the pawl has passed the last tooth of the rack of teeth, the elastic force will make the pawl to move along said third guide surface, and the handle element parts will be free again to move away from each other. During this return movement the pawl will move freely along the even surface. This might take place without any tension from the flexible arm, or the flexible arm may exert a small force against said even surface, so that its guide surface will overlap with the above mentioned second guide surface on the end of the rigid arm.
Preferably, a groove 11 is arranged in the second handle element part 2, in which groove the protruding part 12 of the rack of teeth can move freely when the handle element parts are squeezed together, and then are returned again.
In the embodiment illustrated on the drawings the rack of teeth is arranged on the inside of the rigid arm 4, i.e. on the side facing the pivot connection between the handle element parts 1 and 2. However, it would also be possible to arrange the rack of teeth on the outside of the rigid arm with a corresponding adaption of the guide surfaces for guiding the pawl downwards onto the rack of teeth and then upwards onto the even surface on the opposite side from the rack of teeth.
With reference to
In
| Number | Date | Country | Kind |
|---|---|---|---|
| 0900584-4 | Apr 2009 | SE | national |
