Carriage and rail assembly for a linear positioning system

Abstract

A carriage and rail assembly for a linear positioning system includes a carriage mounted on a threaded screw member at least partially enclosed in a cylindrical housing.

Description

FIELD OF THE INVENTION

The invention relates to devices for controlling linear movement of an object such as a fence on a table saw. In particular, an aspect of the invention involves movement of a positioning carriage along a guide rail, and related assemblies.

BACKGROUND OF THE INVENTION

Significant effort and attention has been directed over the years at automating material handling and manufacturing. Ultimately, material processing equipment must be cost effective to manufacture and use. Therefore, innovation is needed to produce manufacturing equipment that is affordable, in view of its intended use, without sacrificing or comprising precision, accuracy, and overall functional performance.

Table saws may be equipped with a movable fence to allow an operator to set desired cut dimensions. Table saw fences typically are movable along a rail that is bolted along one side of the table saw. An operator may slide the fence back and forth along the rail and then lock the fence in place by means of a locking handle. Many such table saws are sold in a design that requires manual adjustment of the fence.

Sometimes it is desirable to use a table saw in an automated or semi-automated capacity. Digital positioning systems are available for adding on to a table saw that has a manually operable fence. Aftermarket automated fence positioning systems may be cumbersome to install. Some positioning systems are not flexible enough to be easily mounted on different table saw configurations. Thus, an object of the invention is to provide an automated fence positioning system that is easy to install and to adapt to different table saw designs.

Another object of the invention is to produce a table saw control system that is less expensive to produce compared to prior control systems, without compromising speed, precision, and accuracy criteria.

SUMMARY OF THE INVENTION

The invention provides automated fence positioning systems that quickly and accurately reposition a fence in the course of executing a pre-determined cut or sequence of cuts on a table saw. An aspect of the invention utilizes a screw member substantially enclosed in a cylindrical housing. The housing has a longitudinal opening and a guide rail structure adjacent the opening. A carriage is mounted on the screw member and configured to travel back and forth along the guide rail structure. The carriage is rigidly coupled to a fence structure so that rotation of the screw member results in translation of the carriage and associated fence structure.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of an automated fence positioning system.

FIG. 2 is a partial cross-sectional view of the system shown in FIG. 1.

FIG. 3 is a close-up view of a coupling device shown in FIG. 2.

FIG. 4 is a partially exploded view of a rail section and a carriage device configured to move inside the rail.

DESCRIPTIONS OF EXAMPLES OF THE INVENTION

Examples of the invention include numerous aspects and permutations. A preferred rail and carriage assembly implemented on a rip fence is described below with reference to FIGS. 1-4.

FIG. 1 shows a perspective view of a fence control system 20. Fence 22 is provided on a table saw to index a piece of material for cutting relative to saw blade 24. Fence 22 is connected to fence support member 26 which is slidably connected to fence positioning rail 30. Fence positioning rail is coupled to positioning guide rail 34 via clamps 36a and 36b. Carriage coupling device 40 rigidly connects fence support member 26 to a carriage (shown in FIGS. 2-4) which moves inside positioning guide rail 34. Screw member 42 is driven by belt and pulley assembly 44 and a motor inside housing 46 to move the carriage along with carriage coupling device 40, fence support member, and fence 22 to properly position materials for cutting.

FIG. 2 is a cross-sectional view through the assembly of FIG. 1 showing the linkage between internal carriage 50 and carriage coupling device 40. A close-up view of the linkage is shown in FIG. 3. Carriage 50 has a cylindrical portion that has internal threads complimenting threads on screw shaft 42. The cylindrical portion of carriage 50 is contained entirely inside positioning guide rail 34. Carriage 50 also has a flange portion 51 that extends through slot 52 and runs substantially the entire length of positioning guide rail 34. Flange portion 51 includes three T-slots. One T-slot has anti-friction surface material 54 so that carriage 50 can move with a low coefficient of friction relative to T-structure 55 on positioning guide rail 34. Two other T-slots are provided. T-slot 56a receives one or more bolts for securing fence structure coupling device 40. T-slot 56b receives one or more bolts for securing interlock plate member 57a. Interlock device 57b is mounted on plate member 57a, and operates to prevent operation of the machine while the carriage is moving. The T-slot configuration shown in FIG. 3 provides a rigid, sturdy connection between carriage 50 and carriage coupling device 40, thus enabling carriage 50 to move smoothly on a single rail portion 55 without contacting any other internal surface inside positioning guide rail 34. Therefore, the positioning system can operate with significantly less friction making the device more efficient to operate and less expensive to produce compared to prior positioning systems. Alternative slot arrangements may be used. Other types of fastening devices, for example, bolts with nuts, soldered or welded connections, etc. may also be used.

In FIG. 4, a portion of positioning guide rail or housing 34 receives carriage 50. Carriage 50 includes cylindrical portion 60 connected to flange portion 51. Flange portion 51 includes three T-slots 64, 66, and 68 for receiving T-structures, as discussed above and shown in FIG. 3. Collar members 72a and 72b are secured at opposite ends of carriage 50, and are provided with internal threads 74 complimenting external threads on screw 42.

In operation, cylindrical portion 60 is contained in housing 34 where it moves along screw 42 as it rotates. Flange portion 51 extends through longitudinal opening 80 so that T-slots 64, 66, and 68 are positioned outside housing 34 to receive rail structure 55, bolts securing fence structure coupling device 40, and bolts securing plate member 57a, respectively.

The specific embodiments disclosed and illustrated herein should not be considered as limiting the scope of the invention. Numerous variations are possible without falling outside the scope of the appended claims. For example, the invention may be implemented in numerous different machine configurations with varying levels of automation. The invention may also be used to process many different kinds of materials including, but not limited to, wood, wood composites, polymeric materials such as PVC, polystyrene, polypropylene, polyethylene, fiberglass, textiles, etc. In addition to cutting, the invention may be used to carry out other processing steps such as bonding, sewing, heating, UV curing, painting or graphics application, etc. The subject matter of the invention includes all novel and nonobvious combinations and subcombinations of the various elements, features, functions, and/or properties disclosed herein.

Claims

1. A linear positioning system for guiding a rip fence structure on a table saw comprising a rail assembly including a threaded rod substantially enclosed in a cylindrical housing having a longitudinal opening adjacent a T-shaped track, a carriage configured to move back and forth along the rail assembly, the carriage having a threaded portion mounted on the rod, and a flange portion extending through the opening to the outside of the housing, the flange portion having a first T-slot configured to permit smooth sliding of the carriage on the T-shaped track of the housing, and a rigid coupling device connecting the carriage to the fence structure so that movement of the carriage along the threaded rod causes corresponding movement of the fence structure.

2. The system of claim 1, wherein the only contact between the rail assembly and carriage is along the T-shaped track.

3. The system of claim 1, wherein the flange portion has a second T-slot for attaching the coupling device to the carriage.

4. The system of claim 3, wherein the coupling device is attached to the carriage at least at two points.

5. The system of claim 4, wherein the two points define a line substantially parallel to the direction of fence structure movement.

6. The system of claim 3, wherein the flange portion has a third T-slot for attaching an interlock device capable of preventing operation of the saw when the carriage is moving.

7. The system of claim 1, wherein the housing has one or more external longitudinal T-slots for attaching the housing to other structures.

8. The system of claim 1, wherein the first T-slot has low friction material on an inner side of the slot for minimizing friction between the T-shaped rail and first T-slot.

9. A linear positioning system for guiding a rip fence structure on a table saw comprising a rail assembly including a threaded rod substantially enclosed in a cylindrical housing having a longitudinal opening, a carriage configured to move back and forth along the rail assembly, the carriage having a threaded portion mounted on the rod, and a flange portion extending through the opening to the outside of the housing, and a rigid coupling device connecting the carriage to the fence structure so that movement of the carriage along the threaded rod causes corresponding movement of the fence structure.

10. The system of claim 9, wherein the housing has a T-shaped rail adjacent the opening.

11. The system of claim 9, wherein the flange portion of the carriage has a first T-slot configured to permit smooth sliding of the carriage on the T-shaped track of the housing.

12. The system of claim 11, wherein the flange portion has a second T-slot for attaching the coupling device to the carriage.

13. The system of claim 9, wherein the coupling device is attached to the carriage at least at two points.

14. The system of claim 13, wherein the two points define a line substantially parallel to the direction of fence structure movement.

15. The system of claim 11, wherein the T-slot has low friction material on an inner side of the slot for minimizing friction between the T-shaped rail and first T-slot.

16. A linear positioning system for guiding a rip fence structure on a table saw comprising a rail assembly including a threaded rod substantially enclosed in a cylindrical housing having a longitudinal opening adjacent a T-shaped track, a carriage configured to move back and forth along the rail assembly, the carriage having a threaded portion mounted on the rod, and a flange portion extending through the opening to the outside of the housing, the flange portion having a T-slot configured to permit smooth sliding of the carriage on the T-shaped track of the housing, wherein the only contact between the rail assembly and carriage is along the T-shaped track, and a rigid coupling device connecting the carriage to the fence structure so that movement of the carriage along the threaded rod causes corresponding movement of the fence structure.