Key Cutting Device

Abstract

A device for duplicating a pattern key from a key blank including a cutting member, a planar surface mounted adjacent the cutting member, a guide member adapted for engagement with the pattern key, key holding means holding the pattern key in parallel face to face registration with the blank stock key and having a surface in sliding contact with the planar surface for movement of the stock key against the cutting member and the pattern key against the guide member.

Description

BACKGROUND OF THE INVENTION

All presently known devices for making duplicates of standard keys clamp the pattern and blank keys in side by side relation. Because of the distance between the keys, no visual alignment comparison is possible and therefore very accurate clamping means are required. In addition, slight misalignments results in miscut keys.

Most key making devices employ a cutter wheel to cut the new key from blank stock which, in time, becomes worn thereby changing the diameter of the cutter wheel. Unless periodic adjustment is made to compensate for this progressive wear in the cutter wheel, the depth of the cut in the blank will not conform to the depth of cut in the pattern key resulting in miscut and unusable keys.

Because of the manner in which present devices clamp the keys, i.e., side by side; there is no way to check the accuracy of the cuts in the blank with the pattern key except by unclamping the two keys from the device. If the cuts are imperfect, the keys must be placed back in the machine, registered, reclamped, and recut.

SUMMARY OF THE INVENTION

The gist of the present invention is the use of an end mill in combination with a novel clamping means which clamps the pattern and blank keys in face to face relation.

An object of the present invention is to provide a device which will virtually eliminate the miscutting of keys because the face to face positioning of the keys permits instant visual comparison before the keys are unclamped.

A further object is to provide a device which can cut a key more quickly than present devices; requires no deburring and requires no mechanical adjustment even if the cutting member becomes dulled by long use.

A further object is to provide a device which is virtually trouble free and will cut a substantially greater number of keys than present devices before the need to replace the cutting member occurs.

Another object is to provide a keyholder which will accept a wide range of key widths and single or double-sided keys without the need for separate key rests, blocks or other adapters.

Still another object is to provide a safe, compact device which is constructed from a few rugged and inexpensive parts.

A still further object is to provide a device which does not require any special training to operate or the wearing of any protecting equipment during the making of keys.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of the device made in accordance with the present invention.

FIG. 2 is a front elevation view of the device shown in FIG. 1.

FIG. 3 is a side elevation view of the device shown in FIG. 1.

FIG. 4 is a top plan view of the key holding member shown in FIG. 1 made in accordance with the present invention and shown on an enlarged scale.

FIG. 5 is a bottom plan view of the key holder shown in FIG. 4.

FIG. 6 is a side elevation of the device shown in FIG. 4 with portions in cross section taken substantially along the line 6--6.

FIG. 7 is an end elevation of the device shown in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention is a device for duplicating a pattern key 2 by cutting a key from blank stock 3 which consists briefly of cutting means 4, a planar surface 6 mounted adjacent the cutting means and adapted for engagement with the pattern key, keyholding means 8 holding the pattern key in parallel face to face registration with the blank stock key and having a surface 9 in sliding contact with the planar surface for conjoint movement of the stock key against the cutting means and the pattern key against the guide means.

The cutting means includes an end mill mounted for rotation and connected to an electric motor 11 connected to a frame 12. The end mill is shown mounted vertically with the mill above the motor, but the reverse position of the mill and motor could be used.

The device is constructed with a base 13 having walls 14 supporting a table 16. The table and its top surface are dimensioned to permit the keyholder to rest thereon in all positions while the operator is cutting a key.

The guide means and cutting means are mounted in axially disposed relation to each other with only a slight separation between their ends to prevent contact. The guide means, as here shown, is an elongated pin which is dimensionally substantially identical in cross section to the end mill. The pin depends from a support 17 having an upstanding portion 18 which serves as a guard for the end mill and a cantilevered portion 19 which holds the guide pin and serves as a guard protecting the end of the cutting means. One purpose of pedestal 21 is to prevent nearly all portions of the key holder except that vise portion from coming in contact accidentally with the end mill.

The keyholding means consists of a first clamping means adapted for holding the pattern key, a second clamping means adapted for holding the blank stock key, registering means having a first member 22 disposed between the first clamping means and a second member 23 disposed between the second clamping means, each member having a portion adapted for registration with a shoulder 26 of the pattern key and a shoulder 27 of the blank key.

The first clamping means includes an upper flap 28 and a center plate 29. The second clamping means includes a lower flap 31 and the same center plate. Several ways could be provided for applying the clamping force, with the preferred embodiment being shown in the drawings. The top and bottom flaps are formed with openings 32 and 33 with the opening in the bottom flap being threaded to receive a threaded end 34 of a shaft 36 which passes through an opening 37 in the center plate. A second manually engageable thumb screw 38 is connected to the shaft and bearing means 39 may be inserted between an annular face 41 on the handle and the top surface of the top flap to permit easier turning of the handle to apply a relatively greater clamping force. The pattern key is held between a jaw face 42 on the upper flap and the center plate, and the blank stock key is held between a jaw face 43 and the center plate. The center plate should be thick enough to provide convenient separation between the keys.

A feature of the present invention is the ability of the key holder to handle keys of different widths. This is accomplished by providing an adjustment in the first and second registering members. Preferably, the members are connected, or as here shown, the members are actually a single sheet of metal bent in a U-form. The members straddle the center plate and slide thereon. Longitudinal sliding is maintained by providing the key holder with a pair of legs 46 and 47. Elongated slots 44 and 45 in the members permit passage of the shaft of the clamp and sliding movement of the members. As here shown, the center plate is formed with a channel shape thereby providing the legs. The sides of the registering members slidably mate with the inside faces 48 and 49 of the legs.

Infinitely varying locking between first and second positions in the registering means is obtained by providing a first manually engageable clamp means here consisting of a finger engageable knob 50 at the end of a threaded bolt 51 which passes through openings 52 and 53 in the registering members and slotted opening 54 in the center plate to a threaded nut 55 preferably connected to the lower edge of the lower member. When the knob is turned, a land 56 on the underside of the knob presses down on the upper registering member while the lower registering member is pulled upwardly in frictional engagement with the center plate.

Another feature of the present invention is the ability of the holding member to hold one key in clamped position while the other clamp is operated to receive and hold a second key. This function is accomplished by a unique combination of pivots (which also serve as a registering means) and a single spring. The construction is best shown in FIG. 6. The center plate is formed with a pair of registering means which are here shown as a pair of openings 61 and 62. The upper and lower flaps each are formed with pivoting members, here shown as rivets with half round heads 63, 64, 66 and 67 which register with the openings in the center plate. The half round heads hold the upper and lower flaps away from the surface of the center plate and permit the flaps to pivot so as to open and close the jaws of the clamps. The half round heads and openings in the center plate are placed so that they also perform the function of aligning the faces of the clamp jaws. This alignment of the face jaws is important for clamping of the keys but it also thrusts the face of the upper flange slightly forwardly of the lower flap so that when the keyholder is not holding any keys, the upper flap will come in contact with the guide pin thereby preventing the forward edge of the lower flap, which is typically made of ductile iron, from accidentally coming in contact with the end mill, typically rotating at 5,000 rpm, and dulling the cutting edges. Spring means 71 mounted coaxially on the shaft of the manually engageable thumb-screw handle between the annular face on the handle and the top of the top flap biases the upper and lower flaps toward the center plate and permits independent opening of the clamps while holding a key in the other clamp.

Because the upper and lower vise flaps swing in an arc while pivoting, it is necessary to form the openings in the upper flap, the registering members and the center plate, larger than the shaft of the manually engageable handle so that the shaft will not bind on the sides of the openings. To facilitate pivoting, a protrusion 76 is formed integrally with the lower flap with a slanted pressure point 77 and a similar protrustion 78 and slanted pressure point 79 is formed on the upper flap.

In order to check the accuracy of the cuts, a register post means is provided which consists of a linear edge 81 adjacent the planar surface and mounted parallel to the axis of the cutting means. This linear edge is here formed as a protrusion on a stub shaft 82 which may be lowered by registering the linear edge with a gap 83 in a washer 84 and pulling on pin 86.

In operation, the thumb screw is loosened and a blank key is inserted in the lower jaws by squeezing the lower vise flap toward the center plate with, e.g., the right index finger on the pressure point of the lower flap and the right thumb on top of the center plate. This causes the lower flap to rock on heads 63 and 64, pulling the shaft downwardly against the bias of spring 61. Upon release of pressure, the spring holds the key firmly in the jaws of the clamp. The shoulder of the blank key should be brought into registration with the side 90 or 91 of the registration member and the back of the key 92 should fit snugly against the front edge 93 of the registration member.

The original or pattern key is then inserted between the upper flap and center plate by squeezing the upper vise flap at the pressure point. The upper flap rocks on pivot points 66 and 67 and compresses the spring 71. When the pressure is released the spring biases the upper jaws against the pattern key holding it firmly in place. Adjustment of the pattern key to register the key shoulder against edges 96 or 97 and the key 98 against register edge 99 may be accomplished against the spring pressure. When the two keys are in perfect alignment, the thumb screw is further tightened and the blank key is ready to be cut.

The motor is turned on as by flipping switch handle 101, the key holder is slid across the planar surface. To prevent scratching of the surface, the sliding surfaces of the key holder may be coated or fitted with plastic shoes here shown as U-shaped members 9 frictionally fit on the legs 46 and 47. The pattern key is brought into contact with the guide pin 7 and made to move through and to the bottom of each successive cut in the original key. The end mill simultaneously cuts corresponding cuts in the blank.

After the blank key is cut, the accuracy of the cuts may be visually checked without removing either key from the keyholder by merely holding the keys up to the eye and comparing the pattern key with the newly cut key. Very small miscuts are instantly apparent by this eye comparison.

Another comparison can be made by merely sliding the key holder across the planar surface to the register post means. The pattern key is brought into contact with the linear edge 81 and the relation of the cuts in the new key with the linear edge is compared. If there is good registration of the new cuts with the linear edge at all points the key is perfectly cut. Should some misalignment occur, or a cut is not completed or perfectly made, the operator can re-make the cut without removing either key from the key holder.

Claims

I claim:

1. A device for duplicating a pattern key by cutting a key from blank stock comprising:

a. cutting means including an end mill mounted for rotation and adapted for connection to a power source;

b. a planar surface mounted adjacent said cutting means;

c. guide means including an elongated pin mounted adjacent and in axially disposed relation to said end mill and adapted for engagement with said pattern key;

d. said end mill and pin are dimensionally substantially identical in cross section;

e. keyholding means holding said pattern key in parallel face to face registration with said blank stock key and having a surface in sliding contact with said planar surface for conjoint movement of said stock key against said cutting means and said pattern key against said guide means; and

f. said keyholding means including first clamping means adapted for holding said pattern key, second clamping means adapted for holding said blank stock key, registering means having a first member disposed between said first clamping means and a second member disposed between said second clamping means, each member having a portion adapted for registration with a shoulder of said pattern and blank keys respectively.

2. A device as described in claim 1 wherein:

a. said registering means members are connected for joint sliding movement between first and second positions in relation to said clamps for holding keys of different widths and;

b. a first manually engageable clamp means for locking said registering means at infinitely varying points between said first and second positions.

3. A device as described in claim 1 comprising:

a. said first clamping means including an upper flap ad a center plate;

b. said second clamping means including a lower flap and said center plate; and

c. second manually engageable clamp means selectively applying a variable range of clamping force to said first and second clamps and permitting independent opening and closing of said clamps in the lower force range.

4. A device as described in claim 3 comprising:

a. said center plate being formed with a pair of registering means;

b. said upper and lower flaps each being formed with pivoting members registering with said registering means in said center plate and permitting pivoting of said flaps for receiving said keys.

5. A device as described in claim 4 including:

a. spring means biasing said upper and lower flaps toward said center plate and permitting independent opening of said clamps by manually pivoting said flaps about said pivoting members.