Stone working – Sawing – Rotary
Reexamination Certificate
2000-05-17
2002-06-04
Hail, III, Joseph J. (Department: 3723)
Stone working
Sawing
Rotary
C125S016030, C125S014000
Reexamination Certificate
active
06397831
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a saw for cutting hard materials and including a guide rail securable to a cut component, a support displaceable along the guide rail, a saw head having a drive for driving a saw blade and having a drive shaft extending transverse to a longitudinal extent of the guide rail, and a guide region along which the saw head is displaceable within predetermined limits and which is arranged on the support and extends parallel to the drive shaft of the drive and transverse to the longitudinal extent of the guide rail.
2. Description of the Prior Art
A German firm Demco Technic AG produces a saw known as “Piranha” for cutting hard materials such as stone and concrete. The saw has a guide rail, a support, and a saw head. The guide rail is secured to a cut component with suitable fastening elements. The support is mounted on the guide rail for displacement therealong. The support has a plate-shaped base having four guide rollers on one of its sides and supported on the guide rail. On the opposite side, the support is provided with a guide region for receiving and guiding the saw head. The guide region extends parallel to the sides of the base and transverse to the longitudinal extent of the guide rail. The guide region is formed by two, extending parallel to each other and spaced from each other, guide strips between which the receiving element of the saw head is displaceable. For displacing the saw head relative to the support and along the guide rail or in order to be able to lift the saw head off the support, it is necessary to loosen two screws with an appropriate tool and unscrew them out of the base. With this, one of the guide strips becomes disconnected from the base.
Because the screwing and unscrewing of the screws takes a lot of time and cannot be effected without the use of a suitable tool, generally, during the transportation of the saw, the saw head is not separated from the support and is transported therewith though the guide rail is transported separately. Because both the support and the saw head have large weight, the transportation of the saw is cumbersome and tedious.
Accordingly, the object of the present invention is to provide a saw for cutting hard materials the saw head of which can be lifted from a support quickly and easily without use of any special tools and can be easily displaced along the support and be secured thereto.
SUMMARY OF THE INVENTION
This and other objects of the present invention, which will become apparent hereinafter, are achieved by providing quick release means which are arranged between the saw head and the support for connecting the saw head with the support.
The provision of quick release means between the saw head and the support insured lifting of the saw head off the support with a simple handle, without the use of any special tool, and insured an easy displacement of the saw head along the support and attachment of the saw head to the support.
Advantageously, the quick release means includes a locking element arranged on the saw head for securing the saw head to the support, and a lever pivotally supported on the saw head for displacing the locking element parallel to the longitudinal extent of the guide rail against the guide element for the saw head.
With the use of such quick release means the receiving element of the saw head, which is located at the opposite end of the saw head, likewise cooperates with the guide region and is pressed sidewise against the guide region element, so that the guide region becomes clamped between the receiving element and the locking element.
For manufacturing reasons, preferably, the locking element is formed as a slide displaceable by a lever between open and closed positions. The slide can have, e.g., small dimensions, which permits to reduce the entire dimensions of the saw head.
For safety reasons, the saw according to the present invention has, advantageously, a locking pawl which cooperates with the lever and the guide region. Only in the open position of the slide, the locking pawl is able to freely rotate about an axle, which extends parallel to the drive shaft, out of the guide region. In the locking position of the slide, a protrusion, which is provided on the lever, cooperates with a locking surface of the locking pawl to prevent rotation of the locking pawl and to keep the locking pawl in a form-locking engagement with the guide region.
In order to insure that the locking pawl cooperates form-lockingly with the guide region only then when the saw head lies on the support, advantageously, the locking pawl is pivoted, against a spring-biasing force, into a position in which it is form-lockingly engaged in the guide region. The spring insures that, upon lifting the saw head of the support, the locking pawl immediately pivots, about its axle, away form the guide region, breaking the form-locking cooperation of the locking pawl with the guide region.
For displacing the saw head relative to the support along the guide rail, the slide is brought into an intermediate position located between the open and closed positions of the slide. In this position of the slide, the locking pawl form-lockingly cooperates with the guide region. With the lever preventing the pivotal movement of the locking pawl, the saw head can be displaced relative to the support along the guide rail.
In order to insure a reliable attachment of the support by a saw operator and to be able, if needed, to transport the support together with the guide rail, which is secured, e.g., on the support against displacement, the support includes preferably a plate-shaped base having, in a region extending sidewise of the guide rail, a large opening.
In order to be able to fasten with two hands, advantageously, the support base is provided with two opposite regions extending on opposite sides of the guide rail, with each region having a large opening.
For an easy alignment of the guide rail, during mounting of the saw, along horizontal and/or vertical lines, advantageously, the support is provided with at least one indication element which shows an inclination of the support of the guide rail to the horizontal or vertical line.
Preferably, the support has a marking which shows the offset of the saw head with respect to the support along the guide rail. This marking also permits, e.g., an exact determination of a distance between two supports extending parallel to each other.
REFERENCES:
patent: 3323507 (1967-06-01), Schuman
patent: 4192282 (1980-03-01), Fischer
patent: 5545079 (1996-08-01), Larsson et al.
patent: 5676124 (1997-10-01), Lee
patent: 5746193 (1998-05-01), Swan
patent: 5947103 (1999-09-01), Saccon
patent: 6080041 (2000-06-01), Greenland
patent: 6119676 (2000-09-01), Greenland
Plunger Bernhard
Schittl Josef
Selb Michael
Hail III Joseph J.
Hilti Aktiengesellschaft
Sidley Austin Brown & Wood LLP
Wilson Lee
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