Portable cutting apparatus

Abstract

The cutting apparatus of the present invention includes a frame with first and second side members that lie parallel to one another. It also includes two or more cross-members that connect the first and second side members together as well as a cantilever member that lies mounted to one of the other members and extends outwardly of that other member. A tray movably mounted on the frame holds an object for cutting; and a motor and blade assembly mounted to the cantilever member cuts the object. The method of forming this apparatus includes forming openings in the side members and inserting end portions of the cross-members into the opening to form a frame in which the cross-members are parallel to each other and perpendicular to the side members.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to portable saws and more particularly to portable saws for “dry cutting” masonry. Although the present invention finds particular utility in masonry cutting, it may also provide similar cutting functions in a variety of other applications

2. Description of the Prior Art

A variety of building materials such as concrete, masonry, stone and tile require cutting at building sites. These sites continually change as work progresses. Also, these sites typically fill with dust, moisture and other more hazardous and corrosive substances.

Accordingly, the machinery, and more specifically the cutting saws used at these sites should have a light construction for portability. The saws should have a simple construction to avoid malfunction; and they should have a durable construction that avoids wear and withstands dust, moisture and other harmful substances. Also, they should cut precisely, quickly and effectively.

The frame of such a saw should have a rigid construction so that the saw maintains parallelism between the path of travel of the object that the saw cuts and the cutting line of the blade doing the cutting. If the frame cannot maintain this parallelism, the forces generated in the interaction between the blade and the object increase, thereby resulting in increased loading on the motor and uneven wear on the blade.

The cutting saw of the present invention meets all of the requirements outlined above. It is a simple construction that minimizes the expense of fabrication and assembly. It is lightweight and highly portable; it withstands the elements; it has a rigid frame; and it provides precise and effective cutting in dry and dusty conditions.

SUMMARY OF THE INVENTION

In accordance with one embodiment of this invention, a portable cutting apparatus includes a frame with first and second side members that lie substantially parallel to each other. Two or more cross-members connect the first and second side members together while a cantilever member lies mounted on one of the cross-members and extends outwardly of that cross-member. A tray movably mounted on the frame holds an object for cutting; and a motor and blade assembly mounted on the cantilever member cuts the object. The method of forming this apparatus includes forming openings in the side members and inserting end portions of the cross-members into the opening to form a frame in which the cross-members are parallel to each other and perpendicular to the side members.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this invention, one should now refer to the embodiment illustrated in greater detail in the accompanying drawings and described below by way of an example of the invention. In the drawings:

FIG. 1 is a perspective view of the portable cutting apparatus of the present invention;

FIG. 2 is another perspective view of the portable cutting apparatus;

FIG. 3 is a top plan view of the portable cutting apparatus;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 3;

FIG. 5 is a partial and exploded perspective view of a side member of the apparatus frame and rail that helps support and guide the tray of the apparatus;

FIG. 6 is a sectional view taken along line 6-6 in FIG. 2;

FIG. 7 is a sectional view taken along line 7-7 in FIG. 3;

FIG. 8 is a sectional view of a handle for the cutting apparatus of the present invention;

FIG. 9 is an exploded perspective view of the handle;

FIG. 10 is a perspective view of a cantilever member and the motor and blade assembly that it supports;

FIG. 11 is a partial and enlarged perspective view of a joint in the cantilever member;

FIG. 12 is a sectional view showing a pin for locking an articulated cantilever member used in the cutting apparatus of the present invention; and

FIG. 13 is a sectional view taken along line 13-13 in FIG. 12.

While the following disclosure describes the invention in connection with one embodiment, one should understand that the invention is not limited to this embodiment. Furthermore, one should understand that the drawings are not to scale and that graphic symbols, diagrammatic representatives, and fragmentary views, in part, may illustrate the embodiment. In certain instances, the disclosure may not include details which are not necessary for an understanding of the present invention such as conventional details of fabrication and assembly.

DETAILED DESCRIPTION OF THE DRAWINGS

Turning now to the drawings and referring specifically to FIGS. 1 and 2, the portable cutting apparatus 10 generally includes a frame 11, a motor 12, a blade and cover assembly 13, and a tray 14. This apparatus 10 finds particular utility as a saw for “dry cutting” masonry, but it may serve the same or similar function in a variety of other dry cutting as well as wet cutting applications.

The frame 11 is an open structure that allows cuttings and debris to drop to a supporting surface so that they do not accumulate in the apparatus. It includes first and second side members 15 and 16 cast or otherwise formed of aluminum or any other suitable material of high strength and rigidity. These side members have substantially the same size and shape; they have an overall L-shaped configuration; and they define bores for receiving end portions of cross-members of the frame 11, as described below.

First, second and third cross-members 17, 18 and 19, respectively, extend between the first and second side members perpendicularly of the side members. They are round tubes made of aluminum or any other lightweight material of high strength and rigidity. They have substantially the same length to place the first side member in parallel relation with the second side member.

Each of the side members 15 and 16 include a counterbore at the three locations where they receive end portions of the cross-members 17-19. At these locations (See FIG. 6), an end portion of a cross-member (for example, cross-member 17) extends into one of the counterbores of a side member (for example, side member 16). A tube connector C, which lies in the end portion of the cross-member, tightly secures the end portion to the side member by clamping the end portion against the walls of the counterbore.

This connector C includes a ram segment C₁ and a bolt C₂. When placed in the securing position shown in FIG. 6, the connector C lies in a cross-member where it allows turning of its bolt C₂ to move the ram segment C₁ inwardly of the counterbore (that is, to the right in FIG. 6), increase the clamping force on the cross-member against the walls of the counterbore and provide a secure connection. (One example of a tube connector C is the Plastiglide Ram Connector manufactured by ITW of Waterbury, Conn.)

The first and second cross-members 17 and 18 along with the larger of the two leg portions 15a and 16a of each of the first and second side members 15 and 16 (the horizontal portions 15a and 16a) cooperate to form the base of the apparatus 10. Similarly, the second and third cross-members 18 and 19 and the smaller of the two leg portions 15b and 16b of each of the first and second side members 15 and 16 (the vertical portions 15b and 16b) cooperate to form a raised cross bar arrangement for supporting the motor 12 and blade assembly 13 above the tray 14.

A cantilever member 20 lies secured at one end to the third cross-member 19 at the mid-section of the cross-member 19, offset from the mid-point of the member 19 a predetermined distance. The cantilever member 20 supports the motor 12 and the blade assembly 13 at its free, opposite end where an operator has an unobstructed view of the blade assembly and where the combination of these elements provides a center of gravity that facilitates the operation and transport of the apparatus 10. It is an articulated member with a spring 20s (for example, a torsion spring, See FIGS. 10 and 11) which biases the larger of two segments 20a and 20b, the segment 20a, to a raised position shown in the drawings. The spring 20s counters the weight of the segment 20a and assists an operator in the cutting process by moving the blade assembly away from a cutting position when an operator releases the segment 20a. The smaller of the two segments, the segment 20b, remains stationary in the position shown.

At the free, opposite end of the cantilever member 20 (that is, at the free end of the segment 20a), a handle portion 20c (that forms that end) allows an operator to grasp the segment 20a and pivot it downwardly about a pivot 20d that connects the two segments 20a and 20b together. In this manner one may bring the blade assembly 13 into cutting position, as shown in phantom lines in FIG. 4. Stops (not shown) on the segments 20a and 20b limit the range of pivoting motion of the segment 20a so that the cutting blade of the assembly 13, described below, does not strike the tray 14 or cut it.

The handle portion 20c comprises upper and lower halves joined together and secured to the remaining portion of the cantilever segment 20a as shown in FIGS. 8 and 9. These halves are made of plastic or any other material of high strength and rigidity. They support a trigger 20e with which one may activate the motor 12. Control means (not shown) connect the trigger 20e with the motor 12.

As stated above, the cantilever member 20 supports the motor 12 which lies secured along one side of the segment 20a. In certain embodiments, the motor 12 can be secured to the cantilever member 20 such that a majority of the weight of the motor 12 is disposed between the free end and the midpoint of the pinned and free ends of the segment 20a of the cantilever member 20, as shown, for example, in FIGS. 1, 3 and 10. The motor has a housing 12a with openings 12b that ventilate the inside of the housing. A filter 12c (for example, an open cell foam material made of polyurethane ester) lies inside the housing 12a and filters the dust out of the air flowing through the openings 12b, without restricting the flow of air to the motor, to minimize the wear on the motor.

The motor's axle extends through the segment 20a to the opposite side of the segment 20a. There the axle supports and drives a cutting blade 21 of the assembly 13. This blade may be any suitable, conventional diamond or abrasive blade. A blade guard 22 of the assembly 13 lies secured to the cantilever segment 20a and extends over the top portion of the blade 21 to guard it and to protect the operator from the blade when the blade rotates.

Rail segments 23 and 24 (See FIGS. 3-5) lie secured to the horizontal segments 15a and 16b of the side members 15 and 16, respectively, as shown in FIG. 5. These rail segments 23 and 24 are made of steel or any other material of high strength and rigidity; and they support and guide the tray 14 along a predetermined cutting path, as shown in FIG. 3. The precise parallel relationship of the side members 15 and 16 established by those members and the cross-members 17, 18 and 19 provides a precise path for the tray 14.

The side members 15 and 16 have a channel-like configuration in cross-section (See FIG. 4); and the horizontal portions 15a and 16a of those members include protrusions or bosses 15c and 16c that support the rail segments 23 and 24 and receive bolts 25 that secure the rail segments as shown in FIG. 7. In this position, the rail segments provide an unobstructed path for the tray member 14. They provide a path that lies a predetermined distance below the top surfaces of the horizontal portions 15a and 16a of the side members 15 and 16. This recessed positioning of the rail segments and thus the tray provides stability for the apparatus 10.

The tray 14 has a generally rectangular configuration; and it is made of metal, hard plastic, or any suitable material of high strength and rigidity. It defines a groove 14a into which the blade 21 extends so that it may clear an object M (for example, a piece of masonry) that the apparatus 10 cuts. The tray 14 includes rollers 26 rotatably mounted to the main body of the tray 14. These rollers 26 have a pulley-like configuration; and they ride or roll on the rail segments 23 and 24.

When cutting an object M, an operator places the object on the tray 14, grasps the handle portion 20c of the cantilever member 20, activates the motor 12 with the trigger 20e, and lowers the blade down to a cutting position. In this position, a spring loaded pin 27 mounted on the cantilever segment 20b moves into an opening 28 in the segment 20a and locks the blade in the cutting position (See FIGS. 12 and 13). The operator may then move the tray 14 forward past the blade to cut an object M. Alternatively, the apparatus 10 may include more than one opening 28 so that the apparatus may include more than one fixed cutting position.

The process for forming the frame 11 includes casting the side members 15 and 16 out of a material such as aluminum, fly cutting the end faces of the protrusions 15c and 16c that the rail segments 23 and 24 engage and drilling and tapping the holes that receive the bolts 25. The next step involves securing the rail segments 23 and 24 to the side members 15 and 16 respectively, and doing so while the side member castings are “green”, that is, before the castings have hardened to their final state. The rigid rail segments keep the side members straight and prevent them from warping during hardening. One then counterbores the openings that receive the cross-members in the side members 15 and 16. The counterboring provides a precise diameter for the openings and a flat bottom, facilitating a secure and precise connection. The next series of steps comprise cutting three cross-member tubes (for example, extruded aluminum tubes) to the same length, inserting ram segments C, in the end portions of the tubes with a press, and securing the cantilever member 20 to the cross-member with a jig and the motor and blade assembly to the cantilever member. One may then insert the end portions of the cross-members into a pressed fit in the counterbored openings using a press, and tightening the bolts C_{2 .}

By way of a specific example, a portable cutting apparatus of the present invention was constructed using extruded aluminum tubes as cross-members having an acid etched, clear anodized finish and a length of 20.000 inches±0.005, a diameter of 2.0 inches and a wall thickness of 0.125 inches. The horizontal dimension between the centers of the cross-members 17 and 18 (or the corresponding counterbores) was 28.000 inches; and the vertical dimension between the centers of the cross-members 18 and 19 (or the corresponding counterbores) was 11.000 inches. The distance between the end of the member 19 (that is, the end that extends into the side member 15) and the center of the cantilever segment 20b was 8.250 inches; and the distance between the center of the cantilever segment 20b and the other end of the cross-member 19 was 11.750 inches. The distance between the center of the cross-member 19 and the center of the pivot 20d was 2.750; and the distance between the center of the pivot 20d and the center of the motor's shaft or axle was 12.000. The segment 20b of the cantilever member 20 was mounted at a 30-degree angle from the horizontal; and the segment 20a had a 50-degree range of motion from 30 degrees above to 20 degrees below the horizontal. The depth of the counterbores was 0.625 inches; the distance from the bottom of the counterbores to the outer surface of the corresponding bosses of each side member was 1.000 inches; and the distance between the inside surfaces of the rail segments 23 and 24 was 17.75 inches. The rail segments were made of zinc plated, cold-rolled steel having a thickness of 11 gauge and a height of 0.75 inches. Finally, the motor was a 115 volt, 13 amp and 3,500 rpm double-insulated motor.

While the above description and the drawings disclose and illustrate one embodiment, one should understand, of course, that the invention is not limited to this embodiment. Those skilled in the art to which the invention pertains may make other modifications and other embodiments employing the principles of this invention, particularly upon considering the foregoing teachings. Therefore, by the appended claims, the applicant intends to cover any modifications and other embodiments as incorporate those features which constitute the essential features of this invention.

Claims

1. A portable cutting apparatus comprising: (a) a frame comprising: (1) first and second side members disposed in parallel, spaced apart relation,(2) first, second and third cross-members of substantially the same length, said first, second and third cross-members disposed in spaced, parallel relation to one another, each of said cross-members connected in generally perpendicular relation to said first and second side members, and(3) a cantilever member secured to said third cross-member at a middle portion of said third cross-member wherein a segment of said cantilever member defines a pinned end and a free end, said first and second cross-members cooperating with portions of said first and second side members to define a base, said third cross-member being disposed a predetermined distance from said base;(b) a motor secured to said cantilever member such that a majority of the weight of said motor is disposed between said free end and the midpoint of said pinned and said free ends of said segment of said cantilever member;(c) a cutting blade operatively associated with said motor; and(d) a moveable tray disposed on said base for holding an object so that said blade may cut said object.

2. The portable cutting apparatus of claim 1, wherein each of said first and second side members includes a rail portion for supporting and guiding said tray.

3. The portable cutting apparatus of claim 2, wherein said tray includes a body portion and rollers rotatably mounted on said body portion for riding on said rail portions of said first and second side members.

4. The portable cutting apparatus of claim 1, wherein said motor includes a housing with at least one ventilation opening, said motor including a filter for filtering the ventilation air moving through said ventilation opening.

5. The portable cutting apparatus of claim 1, wherein said cantilever member is articulated and includes a spring for biasing one articulated portion to a predetermined position.

6. The portable cutting apparatus of claim 1, wherein said cantilever member is in at least one of a locked cutting position, a raised position, and between said raised and cutting positions.

7. The portable cutting apparatus of claim 1, wherein said cantilever member is arcuately shaped.

8. A portable cutting apparatus comprising: a frame that includes first and second side members, at least three cross-members disposed perpendicularly to said side members, each of said cross-members connected to said side members, and a cantilever member supported by one of said cross-members wherein a segment of said cantilever member defines a pinned end and a free end; a motor secured to said cantilever member such that majority of the weight of said motor is disposed between said free end and the midpoint of said pinned and free ends of said segment of said cantilever member; a cutting blade operatively associated with said motor; and a moveable tray disposed on said frame for moving an object to the blade so that the blade may cut the object.

9. The portable cutting apparatus of claim 8, wherein two cross-members and said first and second side members form a base, said third cross-member being disposed a predetermined distance from said base.

10. The portable cutting apparatus of claim 8, wherein each of said first and second side members includes a rail portion for supporting and guiding said tray.

11. The portable cutting apparatus of claim 10, wherein said tray includes a body portion and rollers rotatably mounted on said body portion for riding on said rail portions of said first and second side members.

12. The portable cutting apparatus of claim 8, wherein said motor includes a housing with at least one opening, the motor including a filter for filtering the air moving through the opening.

13. The portable cutting apparatus of claim 8, wherein said cantilever member is articulated and includes a spring for biasing one articulated portion to a predetermined position.

14. The portable cutting apparatus of claim 8, wherein said cantilever member includes a handle portion at a distal portion.

15. A portable cutting apparatus comprising: a frame with first and second side segments disposed in spaced apart, parallel relation, at least three cross-segments connecting said first and second side segments together, and a cantilever segment connected to one of said cross-segments wherein said cantilever segment defines a pinned end and a free end; a tray disposed on said frame and moveable along a predetermined path; each of said side segments including a track portion for supporting said tray; and cutting means secured to said cantilever segment such that a majority of the weight of said cutting means is disposed between said free end and the midpoint of said pinned and free ends of said cantilever segment; said cutting means disposed above said tray; said first and second side segments being one-piece and integrally formed.

16. The cutting apparatus of claim 15, wherein two cross-segments and said first and second side segments form a base, said third cross-segment being disposed a predetermined distance from said base.

17. The cutting apparatus of claim 15, wherein said track portions are rail portions that support and guide said tray.

18. The portable cutting apparatus of claim 17, wherein said tray includes a body portion and rollers rotatably mounted on said body portion for riding on said rail portions of said first and second side segments.

19. The portable cutting apparatus of claim 15, wherein said cutting means includes a motor, and wherein said motor includes a housing with at least one ventilation opening, said motor including a filter for filtering the air moving through said ventilation opening.

20. The portable cutting apparatus of claim 15, wherein said cantilever segment includes a handle portion extending from a distal portion of said cantilever member.