US2765825A - Rotary mortise cutting tool - Google Patents

Description

,5 D. NEILSON ROTARY MORTISE CUTTING TOOL Filed Dec. 3, 1954 IN V EN TOR.

RGTARY MGRTISE CUTTING TOOL Donald Neiison, Eugene, Oreg.

Application December 3, 1954, Serial No. 472,97?

4 Claims. (Cl. 144-83) This invention relates to a portable rotary cutting tool and fixture adapted for power operation from a standard portable drill chuck to mortise doors, jambs and the like for the reception of a hinge leaf.

One object of my invention is to provide a rotary mortise cutting tool of the above type which is inexpensive to fabricate, is simple to use, and is power operated from a standard portable drill in order to make practical the purchase of the tool by small builders and carpenters while, at the same time, providing a tool which will mortise with accuracy, precision, and speed.

The hanging of a door in a building so that the door will fit precisely the opening provided therefor and will swing freely for the life of the hinges about axes which are plumb demands a high degree of skill and craftsmanship. The conventional method of hanging a door begins with a precise measurement of the door and jamb in order to correlate the location of the hinge leaves to the opposed faces of the door and jamb. Thereinafter, the outline of the recess is scribed on the face of the door and jamb over the areas to be mortised. The wood within the scribed outline then is removed with a hammer and chisel to provide companion mortises for the leaves of the spring. Great care and skill must be exercised in using the hammer and chisel in order to obtain a precise location, the correct dimensions, and an accurate depth in the finished mortise without marring the remainder of the door or splintering oif pieces of wood outside the outline. In some instances, the formation of the mortise is made more difiicult by crooked or cross grain wood and some carpenters never do attain the ability and skill required to hang a door properly. Still further, because of this high degree of knowledge and skill required, the hanging of a door is appoached by the home handyman and the do-it-yourself householder with an apprehension and trepidation which door manufacturers feel unduly is limiting their market.

In partial solution of the above problems, there are today available on the market several mortising tools which are specially constructed for use in forming the recesses in doors, jambs, and the like for the reception of a hinge leaf. I have found, however, that these tools possess certain inherent disadvantages and it is one object of my invention to provide an improved tool from which these disadvantages are eliminated.

Illustrative of those mortising tools now on the market, one type provides a jig or fixture which guides the wood chisel while hammer blows are applied thereto by the workman. This type of tool is but a halfway help to the unskilled workman or householder, however. The chisel still will not cut accurately in crooked or cross grain wood and this type of tool has no depth guide or gauge. Additionally, the average householder who is unfamiliar with and unskilled in the use of a wood chisel cannot attain either an accurate marginal cut or a uniform depth of cut. A second type of mortise cutting tool consists essentially of an electric motor which drives a rotary cutting tool and is provided with a hand grip tates Patent for moving the tool back and forth across the door or iii jamb during the mortising operation. The most obvious disadvantage of this tool is that the gearing and electric motor elements thereof are complex and expensive and require a high selling price far beyond the ability to pay of the small builder, the do-it-yourself handy man or the average householder. Thus, it is quite apparent, that the average householder cannot afford to purchase a specialized and an expensive electric tool merely to hang one or two doors. Similarly, a great many small builders feel they cannot afford to purchase such an expensive tool merely to perform the specialized job of cutting a mortise in doors and jambs. A second disadvantage of the second type of tool is that it is a massive heavy item which is difficult to manipulate, complicated in function, and difiicult to adjust to varying length, width, and depth of cut as required to provide mortises for varying sized hinge leaves.

In view of the above disadvantages and problems inherent in the provision of a simple and inexpensive portable mortise cutting tool, it is one object of my invention to provide a tool which overcomes these disadvantages. To this end, I provide a rotary cutting tool having a pivotal guide which rides upon parallel rails and is powered by a standard portable drill. This tool is simple to operate and to adjust in order that householders can understand and can use the same, is inexpensive to fabricate in order to make practical the purchase of the tool by the small builder and householder, and at the same time, is accurate, sturdy and fast in operation and is unaifected by a crooked or cross grain wood.

A further object of my invention is to provide a rotary mortise cutting tool having an elongated protruding shank which detachably is engageable with the chuck of a standard portable drill, such as an electric or pneumatic portable drill, in order to make practical the use of any of varied power devices to drive the mortising tool. Most householders who are handymen and almost all small builders own such a portable drill. They thus need not purchase another electric motor merely to obtain a mortise cutting tool.

Another object of my invention is to provide a rotary mortise cutting tool in which the fixture or base elements substantially bound and outline the area of the work which is to be cut in order that the worker using the tool can see the area upon which he is working. In conjunction therewith, it is a further object of my invention to provide the tool with a guide of substantial width, which guide overlies the cutting head and is of sufficient width to provide a guard against flying chips generated when the tool is worked in order that the carpenter or workman need not wear protective goggles while mortising a door or jamb.

Yet another object of my invention is to provide a rotary mortise cutting tool in which the cutting tool itself is pivoted into and out of an operative working position thereby giving the carpenter or workman who uses the tool a feel as the work progresses. This feel allows the carpenter to cut a mortise which is of uniform depth in a minimum amount of time and without repeating the movements of the cutting head across the work. It is a factor, however, which is lacking in other mortise cutting tools with which I am familiar.

These and other objects and advantages of my invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, wherein:

Fig. l is a plan view with the tool in an operating position upon the edge of a door overlying a mortise, both the door and mortise being shown in dashed outline;

Fig. 2 is a sectional view, taken substantially on the line 1-2 of Fig. l in the direction of the arrows, showing the tool in inverted operative position in full lines and in an inoperative or retracted position in dashed lines, a standard portable drill chuck being shown joined to the protruding shank of the tool to the right in this figure;

Fig. 3 is an end view, taken substantially in the direction of the arrow 3 in Fig. 1, showing the spring pressed ball which defines a releasable keeper for positioning and holding one of the base members and showing one of the hold down pins engaged with the edge of a door which is traced by dashed outline;

Fig. 4 is a detail view, taken substantially on the line 4 4 of Fig. 2, showing the manner in which the shank of the cutting tool rests upon one of the rails and is guided in a bearing slot in order to obtain an accuracy in the cutting operation; and

Fig. 5 is a detail view illustrating the cooperative movements of a hold down pin and a pivotal release means, a retraction movement being traced by the arrows from the full line position to the dashed line position.

The fixture or guide portion or" my rotary mortise cutting tool comprises a first elongated rail 6 and a second elongated rail 7 which, in operation, are arranged adjacent the side margins of a mortise area M. These rails carry a pair of base members 8 and 9, the rails being parallel to one another and at least the base member being movable longitudinally of these rails. To this end, the fit between the base member 8 and the rails 6 and '7 may be a force fit which fixes the member 8 in position whereas the corresponding fit between the base member 9 and the rails is a sliding fit which permits movement.

In Figs. 1 and 3, I have shown a releasable keeper means which positions the base member 9 at a. preselected loca tion or position as it is moved upon the rails 6 and 7. This keeper means consists of a yieldable compression spring 19 which fits within a tunnel 11 and operatively bears upon a ball 12. The upper portion of the tunnel 11 is closed by a screw threaded cap 13 in order to adjust the force of the spring 16 upon the ball 12.. In cooperation therewith, the rail 6 carries plural spaced grooves 14 (l have shown two such grooves) in which the ball 12 rides. To adjust the position of the base member 9 upon the rails, all that is required is a strong pull or push in order to ride the ball 12 up out of one of the grooves '14 against the force of the spring. The ball and base member then slide along the length of the rail 6. When the base memher 9 overlies a different one of the grooves 14, the ball 12 will enter the groove with a snap due to the action of the spring 10 and will retain the base member in that adjusted position.

In order to secure the tool fixture to the door, jamb, or other piece of work, I provide a pair of identical hold down pins 15. Each of these pins is mounted for reciprocal movement in an elongated tunnel which pierces the corresponding one of the base members 8 and 9. Additionally, each pin isprovided with one pointed end and with one fiat or mushroom shaped end as shown in Figs. 3 and 5. In cooperation therewith, a pivotal release lever 16 is mounted immediately below and in contact with the mushroom head of each pin 15. After the position of the base member 9 is adjusted and the tool fixture is positioned upon the edge of the door D, a hammer like blow is struck upon the mushroom head of each pin 15 causing the pointed end thereof to pierce the wood of the door and hold the base members in place. To release the pins, 21 similar blow or a push is efiected upon the protruding end of the release lever 3.6. Referring to Fig. 5, this blow upon the release lever pivots the same to withdraw the pin 15 from the full line position to the dashed line position;

The cutting tool which rides and is guided by the above described fixture is carried by an elongated guide member 17. This guide has an aperture pivotally and slid ably to carry the guide upon the first rail 6 as shown in Fig. 2. Additionally, an ear 18 projects below and is made integral with the guide 17 for the reception of a longitudinal bearing aperture 19. The opposite end of the guide 17 terminates in a bifurcated portion bounding a longitudinal bearing slot Ztl. The bearing aperture 19 and the bearing slot 20 are aligned one with the other for a purpose now to be described.

A rotary cutting tool having an elongated shank 21, a pilot pin 22, and a cutting head proper 23 rotatably is carried by the guide 17. To this end, the shank 21 is journalled in the slot 2% and the pilot pin 22 is journalled in the bearing aperture 19. In the full line position of Fig. 2 and as shown in Fig. 4-, the bifurcated end of the guide 17 straddles the shank 2i and a portion of this shank rests upon the second rail '7. in this manner, provision is made both for an accurate guide for the cutting tool and for the reception of the shank 21 in the chuck C of a standard rotary drill. In the operative position of the parts shown in full lines in Fig. 2, the cutting head 23 projects below the lower seating surfaces 24 of the base members in order to cut the mortise to the desired depth. In the inoperative dashed line position of Fig. 2, on the other hand, no portion of the cutting head 23 projects below these surfaces 24. Thus, when the cutting tool is pivoted into the cutting position, the carpenter or worker is provided with a feel which is proportionate to the hardness of the wood and this feel continues until the entire mortise has been cut.

In operating my rotary mortise cutting tool, use is made both of a standard drill and of a handle 25 which is made integral with the guide piece 17. In addition, a pair of positioning pins 26 may be employed to vary the effective working area of the tool by varying the eifective length of the surfaces 24 (see Figs. 1 and 3) where the size of the hinge leaves requires the same. Initially, the carpenter or householder will scribe or otherwise mark an utline of the area M which is to be mortised in the door, jamb, or the like. Thereinatter, the positioning pins 26 will be extended where a small mortise is required and will be retracted where a wider mortise is to be cut. At the same time, the base member 9 will be adjusted upon the rails by utilizing the keeper means consisting of the elements 10 to 13 inclusive.

Once the initial adjustments have been effected in accordance with the size of the mortise which is to be cut, a cutting tool 23 is selected which will cut to the desired depth. In actual practice, I have found that one or, at most, two such cutting tools are sufficient for most jobs. The fixture then is positioned upon the door or jamb as shown in Figs. 1 and 2. Thereiuafter, a hammer like blow is struck upon the mushroom heads of the hold down pins 15 in order to hold the fixture in place. A standard chuck C is fitted to the shank 21 of the cutting tool, the drill is turned on, and the mortise cutting tool is pivoted from the dashed line to the full line position of Fig. 2 by grasping both the handle 25 and the body of the drill. The tool and guide then are moved across the length of the mortise area as guided by the rails until the mortise is cut.

As will be apparent, the end boundaries of the mortise M are defined by abutment of the guide 17 with the two base members 8 and 9 and the side boundaries by the physical dimensions of the cutting head 23 and the edge of the door. The blunt end upon the cutting head 23, of course, provides a perpendicular edge for the inner face of the mortise M. The ends of this mortise M, however, will be rounded in conformity with the configuration of the cutting tool 23. It thus is necessary either before or after utilizing my tool to square the ends with a conventional chisel. This most easily is done by striking a single chisel blow at each end prior to operating the tool. Then, after the mortise is cut, the small wedge of wood at the ends easily is removed.

After use, the release levers 16 are struck a sharp blow "thereby retracting the hold down pins 15 and allowing the removal of the fixture and tool from the door jamb. Where a longer mortise M is desired, the base member 9 merely is moved longitudinally along the rails 6 and 7 until the ball 12 engages the difierent one of the grooves 14. Where a wider mortise M is desired, the positioning pins 26 are retracted allowing the edge of the base members to fit against the edge of the door in a position further to the left as viewed in Figs. 1 and 3. These adjustments all are simple to efiect and I have found that even an unskilled householder quickly and readily can grasp the details.

Since a majority of small builders, householders, and handymen possess an electric or pneumatic drill, it will be seen that the purchaser of my rotary mortise cutting tool is saved the expense of purchasing an additional electric motor. This is so since the chuck C of any of numerous standard portable drills will fit the shank 21 of the cutting tool proper. At the same time, it will be appreciated that my rotary mortise cutting tool is extremely simple both in construction and in operation thereby allowing the use of the tool with a minimum know-how and skill. The accuracy with which a mortise can be cut with the tool, even in crooked or cross grain wood, provides a better looking door and one which is hung true and free swinging.

I claim:

1. A rotary mortise cutting tool, comprising a tool fixture having first and second guide rails mutually carrying a pair of spaced base members, elongated guide means mounted intermediate said base members upon said first rail for pivotal movement toward and away from said second rail and for reciprocal movement along said first rail, said elongated guide extending beyond said second rail and terminating in a bearing slot, an ear projecting below that end of said guide carried by said first rail and having a bearing aperture aligned with said bearing slot, and rotary cutting tool means journalled in said bearing slot and in said bearing aperture for rotation with respect thereto.

2. A rotary mortise cutting tool, comprising a portable tool fixture having first and second guide rails mutually carrying a pair of spaced base members, elongated guide means mounted intermediate said base members upon said first rail for pivotal movement toward and away from said second rail and for reciprocal movement along said first rail, and rotary cutting tool mean having a coaxial shaft mounted for rotation about an axis transverse of and normal to both of said rails at an acute angle to the common plane of the rails, said cutting tool projecting below said base members with said shaft means thereof resting upon said second rail in the operative position of the parts yet being pivotally movable with said guide to an inoperative position where no portion of the cutting tool projects below said base members.

3. A rotary mortise cutting tool, comprising a tool fixture having first and second parallel rails mutually carrying a pair of spaced base members, elongated guide means mounted intermediate said base members upon said first rail for pivotal movement toward and away from said second rail and for reciprocal movement along said first rail, said elongated guide extending beyond said second rail and terminating in a bifurcated end bounding a longitudinal bearing slot, an ear projecting below that end of said guide carried by said first rail and having a 1ongitudinal bearing aperture therein, and a rotary cutting tool means having an elongated shank journalled in said bearing slot and a pilot pin journalled in said bearing aperture for rotation about an axis normal to both of said rails, said cutting tool projecting below said base members with the shank thereof resting upon said second rail in the operative position of the parts yet being pivotally movable with said guide to an inoperative position where no portion of the cutting tool projects below said base members, said guide having handle means for effecting said pivotal movement in cooperation with a standard portable drill having the chuck thereof fitted to said cutting tool shank.

4. A rotary mortise cutting tool, comprising a tool fixture having first and second elongated parallel rail mutually carrying a pair of base members adjacent the ends thereof, at least one of said base members being movable longitudinally of said rails, keeper means for releasably fixing said one movable base member in a preselected position upon said rails .in accord with the length of the mortise to be cut, pin means cooperating with said base members and reciprocable with a hammer like blow to fix the position of the base members relative to a piece of work, pivotal release means journalled in said base members engageable with said pin means to retract the latter to an inoperative position, and guide mean detachably carrying a rotary cutting tool and mounted upon said first rail for pivotal movement toward and away from said second rail and for reciprocal movement along said first rail.

References Cited in the file of this patent UNITED STATES PATENTS 809,954 Huber Jan. 16, 1906 1,524,234 Carter Ian. 27, 1925 2,589,458 Toussaint Mar. 18, 1952 2,591,002 Pedron Apr. 1, 1952 2,630,151 Turnbull Mar. 3, 1953 2,693,208 Stewart Nov. 2, 1954

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