Free Fulcrumed Lever Action For The Cutting Wheel Pipe Cutter

Abstract

A free fulcrumed yoke supporting the cutting wheel of a ratchet type pipe cutter within a C-shaped cutting head, the yoke embracing a rider guided for lineal movement relative to and on an adjusting screw having a thrust bearing in its head portion fixed to pull the rider upon turning of the screw when the latter has keyed connection with a spring loaded manipulatable adjusting rod provided with finger engageable triggers, and keeper means for holding the triggered rod in retracted position until the keeper is engaged by the head portion of the adjusting screw as it approaches axial alignment with the adjusting rod.

Description

BACKGROUND

This invention relates to a ratchet type pipe cutter and more particularly to certain novel improvements in construction and operation thereof.

The present invention is directed to improvements in a ratchet pipe cutter of the type as disclosed and described in my U.S. Pat. No. 2,782,500 which issued Feb. 26, 1957. The improvements over my prior patent reside in a more simplified construction both from the standpoint of manufacture and assembly as well as to the achievement of a more efficient and effective operation in the cutting of pipe thereby. In conjunction with the disclosure of my prior patent, the Thomas U.S. Pat. No. 882,432 dated Mar. 17, 1908 has been considered and found wanting in the lack of sufficient leverage and ease of operation in comparison with the improvements set forth in the instant application.

STATEMENT OF INVENTION

The present invention has as a principal object the provision of a simplified form of leverage for the cutting wheel in the cutting head of a pipe cutter. This object contemplates the transmission of a lineal thrust into a lever action for urging the cutting wheel toward the pipe with a minimum of effort on the part of the operator of the tool.

It is another object to provide in the C shaped cutting head of a ratchet type pipe cutter, a yoke type lever for supporting the cutting wheel between a pair of lever arms having their outer ends fulcrumed within the cutting head and their inner ends straddling a screw operated rider to which they are pivotally connected by a pin the ends of which extend into slots formed in the cutter head parallel to the screw for guiding the rider and forceably urging the lever arms and cutting wheel toward cutting engagement with a pipe disposed within the C shaped cutting head.

These and other objects and advantages of the present invention will become apparent in the following description and claims when read in the light of the drawings in which:

FIG. 1 is an exploded perspective view of the component parts of a pipe cutter embodying the present invention;

FIG. 2 is a longitudinal section through the pipe cutter to illustrate parts of FIG. 1 assembled;

FIG. 3 is a plan view of the handle end of FIG. 2 as seen from above in FIG. 2; and

FIG. 4 is a fragmentary view similar to a portion of FIG. 2 and showing the opposite half side thereof.

GENERAL DESCRIPTION

In general the pipe cutter has a C-shaped cutting head 10 rotatably mounted in a correspondingly C-shaped body portion 11 attached to a tubular operating handle 12. A pair of spring loaded pawls 13 and 14 on the cutting head 10 engage annular ratchet teeth 15 on the internal wall of the C-shaped body 11 to effect a one way rotation drive connection between them upon manipulation of the handle 12 about the axis of a pipe to be cut.

The C-shaped cutting head 10 has a gap 16 for receiving pipe or tubing to be cut. A pair of presser rollers 17 are mounted on one side of the gap 16 and a cutting wheel 18 is disposed diametrically opposite the rollers 17 on a leverage 19 for movement toward and from the rollers 17. The movement of the cutting wheel is controlled by an adjusting screw 20 having a rider 21 threadedly mounted on its threaded end for pivotal connection to the leverage 19.

The adjusting screw 20 is journaled in the cutting head 10 at the bight of the C-shape thereof and at right angles to the parallel legs thereof. When the C-shaped cutting head 10 is in register with the C-shaped body 11, the adjusting screw 20 is in axial alignment with the tubular handle 12. A rod 22 extending co-axially of and within the handle 12 has an hexagonally shaped end 23 adapted to have keyed connection with and to fit into a similarly shaped recess formed in the connecting or head end 25 of the adjusting screw 20. The rod 22 is normally urged toward the adjusting screw 20 by a compression spring 26 confined within the handle 12 in a manner well known in the art. It is only when the C-shaped cutting head 10 and C-shaped housing 11 are in register that the adjusting screw 20 can be turned. Turning of the adjusting screw is accomplished by turning of a T shaped head 27 slidably keyed to the free end of the rod 22 as at 22' and mounted for turning movement on the free end of the handle 12.

When the C-shaped cutting head and C-shaped housing are in register, a pipe P to be cut can be inserted into the gap 16 provided. The depth of cut into the pipe P is progressively increased by manual turning of the T shaped head 27 each time the cutting wheel 18 has completed one or more turns about the pipe. It is the degree of pressure and the ease with which this pressure can be applied with the present structure that entails the improvement of the present embodiment of the invention.

Referring to FIGS. 1 and 2 it will be noted that the presser rollers 17 are pivotally mounted in a block 28 so as to expose the rollers 17 to the gap 16 for tangential engagement with a pipe P disposed therein. The block 28 is mounted in the C-shaped cutting head 10 on that leg thereof adjacent the handle side of the cutter housing 11 when the latter is in register with the cutting head. In other words, adjacent the head end 25 of the adjusting screw 20.

The cutter wheel 18 and leverage 19 is disposed on the opposite leg of the C-shaped cutting head 10, i.e., diametrically opposite the pressure rollers 17. The arrangement is such that the leverage 19 and cutting wheel 18 is to be pulled toward the handle side of the C-shaped housing 11 when setting the wheel 18 for the depth of cut into a pipe P in the gap 16.

It will be noted in FIG. 1 that the cutting head 10 is constructed of split C-shaped halves 31 and 32 of substantially identical configurations. Each of these split halves is provided with companion projections serving various purposes in the assembly and construction of the instant invention. In addition to the provision of mounts for pawls 13 and 14 on each of the halves 31 and 32 there is also provided bearing boss halves 33 and 34 for a thrust bearing 35 to receive and support the head end 25 of the adjusting screw 20. From these bearing boss halves 33 and 34, guide shoulders 36-37 extend parallel to the adjusting screw 20 for engagement with one flat surface of the rider 21 on the screw 20. Each split half 31 and 32 is also provided with a fulcrum block in the farm of fixed abutments 38-39 adjacent its outer end and inwardly the gap 16 of that leg of their C-shape, which leg is opposite the one supporting the presser rollers 17 in the cutting head 10.

The leverage 19 comprises a pair of lever arms 40 and 41 each of dog-leg shape having their enlarged ends 42 pivotally connected to the rider 21 by a pin 43. The pin 43 has its ends extending into grooves 44 and 45 formed on the respective halves 31 and 32 of the cutting head 10. These grooves 44 and 45 are formed parallel to the adjusting screw 20 and serve to guide the rider 21 parallel thereto upon turning of the rod 22 by manipulation of the T shaped head 27 on the end of the handle 12.

The opposite ends 46 of the lever arms 40-41 are united by a cross pin 47 having its ends extending into grooves 47' formed in the outer ends of the halves 31-32 between the gap 26 and the fixed abutments 38-39. The grooves are slightly wider than the diameter of the ends of the cross pin 47 for guiding the ends 46 of the lever arms substantially parallel to the gap 16 and for simultaneous bearing against the fulcrum blocks provided by the fixed abutments 38 and 39 when the rider 21 is drawn toward the handle by manipulation of the adjusting screw 20.

The lever arms 40-41 are likewise united by an axle shaft 48 which extends through the cutting wheel 18 at the knee portion of the dog-leg lever arms 40 and 41. By this arrangement the cutting head diametrically opposite the presser rollers 17 and disposed to advance its cutting edge into the gap 16 upon fulcrumed action of the leverage 19 against the fixed abutments as above explained.

It should here be noted that the two split halves 31 and 32 of the C-shaped cutting head 10 are secured together by three machine screws 50 and a fourth such screw 51. Two of the three machine screws 50 extend through each of the pawls 13 and 14 for pivotally mounting them in the cutting head 10 whereas the third of these screws 50' extends through the fixed abutment fulcrum blocks 30-39 to secure them together. The fourth machine screw 51 extends through the mounting block 28 for the rollers 17, which block 28 is embraced between projections on the split C-shaped halves 31 and 32 to maintain the rollers 17 at the diametrical axis of the C-shaped cutting head 10. By this latter arrangement the mounting block 28 is adjustable diametrically transversely of the C-shaped cutting head 10. For this reason each of the split halves 31 and 32 of the cutting head is provided with at least two bored holes 52 and 52' along the diametrical axis of the C-shaped cutting head either of which holes may receive the machine screw 51 in addition to the latter providing a part of the means for securing the split halves 31 and 32 together.

Means 53 for retracting the keyed end 23 of the spring leaded rod 22 relative to the adjusting screw 20 comprises a trigger 54 disposed adjacent the T-shaped head 27 on the free end of the handle 12. The trigger 54 consists of one or a pair of finger engaging extensions projecting from a hub 55 freely mounted on the rod 22 and extending through a slot or slots 56 in the tubular handle 12. The hub 55 is disposed to bear against a flange 57 on the rod 22 on that side thereof opposite the compression spring 26. The arrangement is such that when the T-shaped head 27 is in the palm of a human hand, the first and second fingers of such hand are in a position to engage the triggers 54 and pull the rod 22 away from the cutting head 10 against the action of the spring 26, the free end 22' of the rod 22 being shiftable within the T-shaped head on the handle 12.

The hexagonal end 23 of the rod 22 is thus withdrawn from keyed connection with the adjusting screw 20 and out of the orbit of swing of the cutting head 10 within the C-shaped body 11. A spring pressed keeper 58 is mounted on the C-shaped body 11, midway between the pawls and ratchets and at right angles to the axis of the rod 22 on the handle side of the head end 25 of the adjusting screw 20. The keeper 58 is constantly urged toward the hexagonal end 23 of the rod 22 such as to traverse the axis thereof when the rod is withdrawn (See FIG. 1). Pin means 59 in a milled side 60 of the keeper 58 serves to limit the movement of the keeper beyond blocking position relative to the spring loaded rod 22.

The cutting head 10 is thereby released for turning within the C-shaped body 11 as the handle 12 is turned anti the pawl and ratchet drive and driven thereby during cutting of the pipe P. As the cutting head 10 is about to complete one full revolution within the C-shaped body 11, as illustrated by the arrows in FIG. 4, the inner end of the keeper 58 is brought into contact with the head end 25 of the adjusting screw 20. As the C-shaped body 11 is moved further anti-the pawl and ratchet drive connection the keeper 58 is pressed by the head 25 back sufficiently to release the rod 22 from the keeper. The keeper 58 has a beveled end 61 disposed for camming action of the spring loaded rod 22 whereby the latter forces the keeper out of latching engagement with the rod 22. Thereafter as the adjusting screw 20 becomes aligned axially with the rod 22, the hexagonal end 23 of the latter will again be forced into the companion recess in the head 25 of the adjusting screw. The rod 22 and adjusting screw are then again in keyed connection as shown in FIG. 2 to enable the person operating the tool to turn the T shaped palm head 27 to draw the rider 21 toward the handle 12. Thus the pivoted end of the leverage 19 is again urged toward the handle 12 with the rider to employ the fulcrum action afforded in the leverage between the lever arms 40-41 and the fixed abutments 38-39 to force the cutting wheel into the pipe to be cut.

Having thus described the improvements in my new cutting tool in specific detail it will be appreciated that the same may be modified, altered and/or varied without departing from the spirit or scope of my invention therein as called for in the appended claims.

Claims

What I claim as new and desire to protect by Letters Patent is:

1. In a ratchet type pipe cutter tool having a C-shaped cutting head arranged for one way rotative movement within a ratchet formed on a C-shaped body, the C-shaped cutting head and C-shaped body being adapted upon register with each other to provide a C-shaped gap to receive a pipe to be cut, and having a tubular handle extending from the bight of the C-shape body in offset relation and transverse to the C-shaped gap therein for turning the C-shaped body relative to the C-shaped cutting head, the combination therewith of:

a. a pair of presser rollers mounted in such cutting head and supported on the handle side of the C-shaped gap therein when the cutting head is in register with the C-shaped body;

b. an adjusting screw journaled in the cutting head for axial alignment with the tubular handle during register of the C-shaped cutting head with the C-shaped housing and having a keyed connecting end disposed to then face the handle side of the C-shaped body;

c. a spring loaded retractable drive rod turnably mounted within the tubular handle and having an inner keyed end urged toward and adapted for keyed connection to the keyed connecting end of said adjusting screw for turning the latter;

d. a rider threadedly connected to said adjusting screw;

e. fixed abuttments adjacent the open end of said C-shaped cutting head on that side thereof opposite said presser rollers and inwardly of the C-shaped gap of the cutting head;

f. a lever arm mounted in the C-shaped cutting head on that side of the gap thereof opposite said presser rollers, said lever arm having one end pivotally connected to said rider for movement therewith and it opposite end disposed for fulcrumed bearing against said fixed abutments within the C-shaped cutting head;

g. a cutting wheel journaled within said lever arm diametrically opposite said presser rollers with its cutting periphery disposed to extend into said C-shaped gap and in the plane of rotative movement about a pipe therein; and

h. means between the said opposite end of said lever arm and said cutting head for maintaining the said opposite end of the lever arm on that side of the gap opposite the presser rollers and in fulcruming engagement with said fixed abutments during movement of said rider by said adjusting screw.

2. The cutting tool in accordance with that of claim 1 including guide means between said cutting head and said rider comprising:

a. means formed on said cutting head parallel to said adjusting screw and adjacent opposite faces of said rider; and

b. means on said opposite faces of said rider engaging said means formed on said cutting head for guiding said rider parallel to said adjusting screw during turning of the latter.

3. The cutting tool in accordance with that of claim 2 including a bearing boss therein in the cutting head, and a thrust bearing on the keyed connecting end of said adjusting screw for maintaining the latter in relatively fixed relation to said cutting head during turning of said adjusting screw and guided movement of said rider therealong.

4. The cutting tool in accordance with that of claim 1 including a bearing boss therein within the cutting head and a thrust bearing on the keyed connecting end of said adjusting screw for maintaining the latter in relatively fixed relation to said cutting head during turning of said adjusting screw and guided movement of said rider there along.

5. The cutting tool in accordance with that of claim 4 in which said lever arm is in the form of a dog-leg shaped yoke having two arms and one end thereof embracing said rider, guide slots formed in said C-shaped cutting head parallel to said adjusting screw and on opposite sides of said yoke arms and rider; and pin means for pivotally connecting the embracing ends of said yoke arms to said rider and extending into said guide slots for guiding said rider parallel to said adjusting screw upon turning of the latter.

6. The cutting tool in accordance with that of claim 5 in which the opposite ends of said yoke arms have pin and slot guidance within said cutting head for maintaining said opposite ends of said yoke arms from movement into the gap in the cutting head and for fulcrumed bearing relation to said fixed abutments therein.

7. The cutting tool in accordance with that of claim 6 including a spring urged keeper mounted in the C-shaped body for movement transversely of the axis of the inner end of said retractable drive rod upon retraction of the latter for holding the drive rod in retracted position during rotative movement of the cutting head within the C-shaped body, said keeper being disposed in the orbit of rotation of the keyed connecting end of said adjusting screw as it approaches axial alignment with said spring loaded drive rod for releasing the latter for keyed connection to said adjusting screw.

8. The cutting head in accordance with that of claim 7 including a palm grippable T head rotatably mounted on the free end of the tubular handle for turning said spring loaded retractable drive rod relative thereto, and finger engageable trigger means on said drive rod in proximity to said palm grippable T head for retracting the drive rod against the action of its spring.