"METHOD AND APPARATUS FOR FORMING CUTS IN PROBES, GUIDE WIRES AND FELLOWS"BACKGROUND 1. FIELD OF THE INVENTIONThe present invention relates to making precision cuts in probes and guide wires. Specifically, a device is provided for retaining, advancing, rotating and then cutting a probe or guide wire, which is capable of manipulating the probe or guide wire in two degrees of freedom to allow precision control of the location of the cuts. Various clamping mechanisms are provided for manipulating the probe or guide wire as well as the mechanisms for detecting wear of the saw blades used to make the cuts that result in controlled variation in mechanical properties.
CURRENT STATE OF THE TECHNIQUEMaking cuts in probes and guide wires requires precision in order to ensure reliability due to the medical applications where they are used. However, it is also important to control the production costs of -so that the costs of the health care industry can be minimized. The current state of the art is typified by these devices such as rectification wires, coils and laser to make the cuts. These devices often suffer from high cost or inaccurate or difficult control mechanisms to properly place both the device to make the cut and the cylindrical object to be cut. What is needed is a method and apparatus for making cuts in probes and guide wires that allows precise control of the characteristics of the cuts. This involves retention of precision, advance and rotation of the generally cylindrical object, while at least one saw blade is advanced by itself to make the cut and retracts later.
OBJECTS AND COMPENDIUM OF THE INVENTIONAn object of the present invention is to provide a method and apparatus for forming precision cuts in probes and guide wires. Another object is to provide a method and apparatus for forming precision cuts in cylindrical objects.
Still another object is to provide a method and apparatus for forming precision cuts by manipulating a cylindrical object in two degrees of freedom to control the parameters of the cuts. Yet another object is to provide a method and apparatus for retaining, advancing and rotating a cylindrical object to be cut. Still another object of the invention is to provide a method and apparatus for increasing the performance of a device that cuts err cylindrical objects, providing multiple saw blades in a single cutting tool. Another object is to provide a method and apparatus for detecting the degree of wear of a saw blade in order to more accurately control the position of the saw blade. These and other objects of the present invention are obtained in a preferred embodiment of a device for making cuts in a probe, guide wire or other cylindrical object. The device includes a base having at least one circular saw blade mounted on a spindle member, and a clamp for manipulating and positioning the object to be cut. The circular saw blade is rotatably mounted on a spindle member. The spindle member is free to move vertically and horizontally -with respect to the base to in this way control the location, length, depth and angle of the cuts in a cylindrical object placed adjacent to it. The clamp is able to retain the object to be cut, as well as to place it for example by rotation to thereby expose the entire circumference of the cylindrical object to the saw blade. Releasing the clamp, a pressure roller advances the cylindrical object before the clamp is reattached in order to retain it securely the cylindrical object to be cut. Another object of the invention is the ability to make precision cuts providing means for controlling the rotation and advance of the object to be cut and the movement of the spindle member of the saw blade. Sensors are also provided to enable the detection of wear on the saw blade to send signals necessary for resetting or adjusting the location of the spindle member of the saw blade to compensate. Another object is the ability to simultaneously make a plurality of cuts in the object. This is achieved with a saw blade having a plurality of blades in parallel. Even more cuts can be made by providing more than one spindle member of the -Saw blade, where each is independently movable in two degrees of freedom. Another aspect of the invention is to provide more than one spindle member so that the blades can make precision cuts simultaneously at different locations along the length of the barrel. These and other objects, features, advantages and alternative aspects of the present invention will become apparent to those skilled in the art when taking into account the following detailed description in combination with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGSFigure IA is a front elevation view of a preferred embodiment made in accordance with the principles of the present invention. Figure IB is a side elevational view of the invention shown in Figure IA. Figure 2 is an alternative embodiment of a vertically moving member shown in inverted orientation with respect to Figures IA and IB. Figure 3 is an alternative embodiment of a horizontally moving member shown reversed in orientation with respect to Figures 1A and IB.
-Figure 4 is a functional diagram of the preferred embodiment showing a control means and a sensor means for controlling the determination of the position and movement of the components. Figure 5 is a functional diagram showing the signals that pass between the components when an electrical conduction sensor is used. Figure 6 is a functional diagram showing the signals passing between the components when using a mechanical advance resistance detection sensor. Figure 7 is a functional diagram showing the signals that pass between the components when a rotation sensing sensor is used. Figure 8 is a functional diagram showing the signals that pass between the components when an optical detection sensor is used. Figure 9A is a front elevation view of an alternative embodiment for the fastening means. Figure 9B is a side elevational view of the alternative embodiment for the fastening means of Figure 9A. Figure 10 is an alternative saw blade assembly that can be used in all embodiments of the present invention.
Figure HA is a top elevation view of an alternative clamping device. Figure 11B is a view of the lateral elevation of the alternative clamping device of Figure 11B. Figure 12 is an alternative embodiment that uses two saw blade assemblies to simultaneously make incisions in the probe.
DETAILED DESCRIPTION OF THE INVENTIONReference will now be made to the drawings wherein the various elements of the present invention will be provided with numerical designations and wherein the invention will be discussed in order to enable a person skilled in the art to make and use the invention. The present invention is illustrated in Figures IA and IB. Figure 1A is a front view of the preferred embodiment of the invention, and shows the system for forming precision cuts in a probe, a guide wire, or other cylindrical objects. For purposes of keeping in mind the intended use of the present invention, reference will be made to a probe as the object being cut, even if any cylindrical object can be replaced by the probe. However, reference to the probe is only for convenience of writing in terms of a specific cylindrical object, and should not be considered a material limitation of the invention. However, referring to a probe keeps in mind the object of having a very precise cutting device, where accuracy is important in most medical applications. In addition, a probe only in one modality of a medical application, but that easily represents the need for precision. The system 6 shown in Figures IA and IB consists of several elements including a base member 10 to support the structure. Coupled in sliding engagement with the vertical base member 12 there is a vertically movable member 14 having a first vertical coupling face 16 and a first horizontal coupling face 18. The vertical coupling face 16 engages a vertical coupling face 20 of the base member. The meism 22 to allow the sliding coupling between the vertical coupling face 16 and the vertical coupling face 20 of the base member may be any suitable apparatus. The important consideration is that the vertically movable member 14 is not allowed to move horizontally, or the accuracy of the system will be compromised. Therefore, the tolerances of mechanism 22 must necessarily be small. A good example of an appropriate mechanism 22 is well known to those skilled in the art as a cross roller carrier slide. The shape of a vertically movable member 14 is shown here as a small backward "L". An alternative form for the vertically movable member 14 is shown in Figure 2. The member 14 is released in comparison with the embodiment of Figure IA. The important feature of member 14 is that it provides two faces 16, 18 that can be slidably coupled to move vertically and provide a second face where another member can be slidably coupled to move horizontally. The system of Figures IA and IB may also consist of a horizontally movable member 24 having one end 26 of the spindle and a second side 28 of horizontal coupling. This horizontally movable member 24 is slidably coupled on its second horizontal coupling face 28 with the member 14 vertically movable on its first horizontal coupling face 18. It should be noted that the vertically movable member 14 and the horizontally movable member 24 are capable of moving independently of one another. In this way, the system achieves two independent degrees of freedom of movement.
-The spindle end 26 of the horizontally movable member 24 provides a horizontal slot 30 in which a spindle 32 is positioned. The slot 30 is generally circular to serve as a receiver for the round arrow 34 of the spindle 32. Arrow 34 of the spindle at least one circular saw blade 38 is positioned at one working end 36 thereof. The circular saw blade 38 is placed vertically on the spindle arrow 34, but can also be angled in other embodiments. The spindle arrow 34 is coupled to a drive motor by gears, belts, direct drive or any other suitable means (not shown), which will cause the arrow 34 of the spindle to rapidly rotate. The drive motor (not shown) can be placed in any appropriate location relative to the spindle shaft. In the preferred embodiment, the arrow 34 of the spindle is driven by a brushless direct current motor through a toothed timing belt. The circular saw blade 38 is typical of those found in the art. In a preferred embodiment, the cutting edge 40 of the saw blade 38 is coated with industrial diamonds. The means for retaining and otherwise manipulating a probe 8 to be cut is the fastening member 50. The fastening member 50 consists of two main assemblies: the clamp 52 and the clamping power supply means 54 (supply), or the device feeding the probe 8 to and then through the clamp 52. The clamping member 50 The fastener also engages with the base member 10 and is positioned to retain the clamp 52 in a position to easily feed the probe 8 to the circular saw blade 38. In the preferred embodiment, the clamp 52 is of the type known to those skilled in the art as a clamp clamp. A clamping clamp is a slotted cylindrical clamp inserted tightly into the tapered inside of a sleeve in a lathe to hold a cylindrical workpiece. Figure 1A, the cylindrical shape of the clamp 52 is visible. It is grooved since the holding arms 58 are spaced apart from each other so that they can be pulled away from the probe 8 when disengaged and then securely joined around the probe 8 when engaged. In a preferred embodiment, a desirable feature of the clamp 52 is that it can be rotatably mounted within the clamping member 50. The clamp 52 is then rotated to place a different portion of the surface of the probe 8 on the saw blades 38. The mechanism for rotating the sample clamp 52 generally at 56 and consists of the clamp 52 which is retained in a frame that can rotate with respect to the saw blade 38. The clamp feed means 54(supply) shown in Figure IB is shown in this preferred embodiment as consisting of a pressure roll assembly 60, 62 working in conjunction with a feed roll 66. As Figure IB should clarify, the pressure roller assembly 60, 62, supplies the probe 8 to the clamp 52 using friction created between two opposing members 60, 66. The upper member is the pressure roller 60. The lower member is the feed roller 66. The feed roll 66 has a shaft 68 mounted on the clamp feed means 54 so that the feed roll 66 can roll. The pressure roller 60 is placed on the end of a lever arm 62 that is pivotally pivoted on the pivot end 70 Positioned remotely from the pressure roller assembly along the length of the lever arm and a hole 72. One end of a spring 64 is inserted through it and the other end of the spring 64 engages another hole 74. with the clamp feed means 54. The spring 64 provides the necessary tension -so that the feed roller 64 pushes the probe 8 towards the opening 52. Having described most of the components in the preferred embodiment of the probe cutter assembly 6, the operation of the assembly 6 is as follows. First, the uncut probe 8 is placed between the pressure roller 60 and the feed roller 66. This can be accomplished by raising the lever arm 62 by elongating the spring 64. Releasing the lever arm 62 causes the pressure roller 60 to be pushed down against the feed roller 66, with the probe 8 positioned therebetween. A drive mechanism (not shown) engages with the feed roller 66 to cause it to roll and thereby push the probe 8 towards the clamp 52. The clamp 52 must be in the unlatched position (the hole through the clamp is larger than the diameter of the probe 8) so that the probe 8 can be easily fed therethrough. After passing through the clamp 52, the probe 8 is fed far enough past the circular saw blade 38 so that it is in an appropriate position for an incision to be made in or through its surface. When the probe 8 is correctly positioned, the clamp 52 is engaged and the saw blade 38 is-advances to make cut contact. Prior to cutting, the saw blade 38 will always be placed in a retracted position. The retracted position is both vertically below and horizontally pulled to the state of the probe 8. The first movement of the saw blade 38 is 1) the horizontal advance towards the probe 8. This is achieved by moving the member 24 horizontally movable relative to the vertically movable member 14 to which it is fixed. The horizontally movable member 24 moves until it reaches the depth of the incision to be made in the probe 8. The next step 2) comprises the vertically movable member 14 moving upward relative to the base 10 in which it engages to make the cut in this way. The saw blade 38 is then retracted immediately by moving the vertically movable member 14 away from the probe 8. The horizontal member moves only when the next cut is at a different depth or when the entire cutting operation has been completed. If another cut is to be made, clamp 52 is released in step 4). The probe 8 is then fed through the clamp 52 by a feed roll 66 as in step 5). The clamp 52 is then re-engaged in step 6) and, if necessary, the clamp 52 is rotated to expose a different position of the probe 8 to the saw blade 38. The saw blade 38 then move horizontally if the cutting depth will change, and then vertically to make the cut and repeat steps 1) to 7) as frequently as necessary until all the incisions have been made or that the probe 8 is no longer is capable of being held by the feed roller 66 and the opposite pressure roller 60. The foregoing description of the operation of the probe cutter system 6 describes the different roles that are served by the clamp 52. When the circular saw blade 38 is making a cut in the probe 8, the clamp 52 holds the probe 8 constant. When the cut has been made in the probe 8, the probe 8 is fed through the clamp 52 causing the clamp to disengage from around the probe 8. After disengaging the probe 8 is fed through the clamp 52 until the next point of incision in the probe 8 is in a position relative to the saw blade 38. The clamp 52 is re-engaged in order to be tightly placed around the probe 8 to again prevent movement of the probe 8 during cutting. It should be recognized from the foregoing description that the width of a cut in probe 8 is limited to the width - -of the circular saw blade 38. A wider cut therefore requires that the probe 8 be advanced slightly beyond the saw blade 38. However, the advance is not carried out while a cut is made. Saw blade 38 should be removed so that clamp 52 can be disengaged from around probe 8 while being advanced. This is necessary because it is allowed to make the cut of the probe 8 when the clamp is disengaged creating a useless cut if it is not imprecise. Another vital component of the assembly 6 is a position detecting means. While now understanding the manner in which the probe 8 is cut off, the manner in which the feed roller 66 knows when to stop feeding the probe 8 through the clamp 52 or how much the clamp needs to rotate is not explained. 52 before the cut begins. In other words, precision cutting also requires precision placement of the probe. Precise positioning requires sensors that can detect where the probe 8 is in relation to the saw blade 38 and the clamp and then provide this information to a certain control device that coordinates the movement of all components by sending the necessary signals in order to correctly place all the components of the system 6.
This concept is generally shown in the functional diagram of Figure 4. The probe cutter system 6 is shown as having entries from the control means 80 for positioning the vertically movable member 14 shown as the arrow 82, the entry shown with the arrow 84 for placing the horizontally movable means 24, the arrow 86 which designates the input for controlling the rotation of the clamp 52, and an arrow 88 which designates an input for controlling the feed roller 66. Two control inputs for the clamp and the Spindle motor are also shown as arrows 87 and 89, respectively. The functional diagram in Figure 4 also shows a sensor means 90 for receiving position information from system 6 as indicated by arrow 92. This information is transmitted to control means 80 as indicated by arrow 94 so that can be processed and the correct control signals 82, 84, 86 and 88 can be transmitted to the system 6. There are several alternative methods for determining the position of the probe 8 relative to the saw blade 38. These devices can all be replaced as sensing means 90 of Figure 4. The first device is an electrical conduction detector circuit 100 shown in the form of a functional diagram as in Figure 5. Sometimes the case is that the materials used in the probes 8 They are electrically conductive. In addition, the saw blade 38 can also be electrically conductive. Consequently, placing the saw blade 38 in contact with the conductive probe 8 can result in an electrical circuit being completed. By moving the saw blade 38 sufficiently slowly so as not to make abrupt contact with the probe 8, the momentum of the contact can be used as a reference point, so that the saw blade 38 can move at the appropriate horizontal distance to make the desired cut. Figure 6 shows an alternative method of position detection. In this embodiment, the means for detecting resistance to the mechanical advance is coupled to the saw blade 38. The advance resistance detecting means 102 may be coupled to either the drive means 104 of the saw blade 38, or the spindle 32 of the saw blade 38. In other words, the detection means 102 to the "advance" is any device suitable for detecting when a forward resistance force is encountered by the saw blade 38. For example, a device for this object is a torque transducer which measures the torque load of the arrow that rotates blade 38.1Figure 7 shows a related method of position detection which is the use of a rotation detector means 106 which still detects the slight partial revolutions of the saw blade 38 as the spindle is vertically oscillated and progresses horizontally slowly . With the blade 38 not rotating, the rotation of the blade 38 will occur when there is a slight contact between the blade and the probe. A final method for detecting the position of the saw blade 38 relative to the probe 8 is to use an optical detector 108, as shown in the form of a functional diagram in Figure 8. The optical detector means 108 is positioned in such a way that can detect the contact between the saw blade 38 and the probe 8. There are several optical devices that can be used to implant this detector 108. An aspect of the invention that is related to the various means 90 detectors described above is that Not only is it important to know the position of the blade, but it is also important to know the degree of blade wear. All of the aforementioned sensor modalities are inherently capable of compensating for the wear experienced by the blade 38. In other words, none of the methods for determining the exact position of the blade 38 depend on the -Assumption that the size of the blade 38 is constant. All sensor modes 90 account for the wear of the saw blade 38 by dynamic determination of the position that is not based on a predetermined size of the saw blade 38. Instead, the sensors 90 determine when the contact is being made and adjust the position of the blade 38 or of the probe 8 accordingly. Preferred variations of the embodiment are illustrated in Figures 9A and 9B which show that the securing means 52 has been modified. As will be seen in Figure 9A, a stationary support surface 110 is provided with a slot 112 therein to hold the probe 8 from below. Slot 112 guides and retains probe 8 before, during and after cutting. Holding the probe 8 not only allows a more precise cut but also prevents damage to the probe 8 that might otherwise occur. The movable fastening member 114 or anvil is also provided to apply force in this manner to the probe 8 which is clamped between the anvil 114 and the grooved support surface 110. Figure 9B also shows that the anvil 114 has a mechanism 116 that allows the anvil 114 to move vertically with respect to the support surface 110.
-Figure 10 illustrates a modification with respect to spindle arrangement 38 and saw blade 38 shown in Figures 1A and IB. Specifically, a plurality of saw blades 38 are shown as being mounted in parallel in the same spindle 32. This also means that the saw blades 38 are necessarily coaxial. It is also preferred that the saw blades 38 have the same diameter so that no individual saw blade 38 makes a deeper incision in the probe 8 than in any of the others. However, it should be evident that if the spindle 32 or the saw blades 38 are easily separable from the system 6, then the saw blades of varying diameters could be mounted on the same spindle 32 to achieve a consistent pattern of cuts having different depths . Figure HA shows a clamp mechanism 120 to be used in conjunction with the multiple saw blade assembly 38 of Figure 10. The mechanism 120 of the clamp is capable of retaining a probe 8 in its place while the probe 8 is cut by the plurality of saw blades 38. This is achieved by providing a clamping surface 122 having a depression or slot 124 for receiving the probe 8. Coupled with the clamping surface is a leaf spring 126. The leaf spring 126 consists of several fingers 128 which force the probe 8 to remain in the slot 124 where it is cut. Placed perpendicular to the slot 124 and extending from the clamping surface 122 completely through the clamping mechanism 120 to the back side 136, there are a plurality of grooves 130 (which produce the clamp fingers 132) through which the saw blades 38 extend to thereby cut the probe 8. The fingers 128 of the leaf spring 126 are typically spaced apart from each other. distance equal to the spacing between the plurality of slots 130. This ensures that the saw blades 38 do not inadvertently contact the leaf spring fingers 128 while cutting the probe 8. To allow the probe 8 to be fed through the the groove 124 in the clamping surface 122, there must be a mechanism for lifting the fingers 128 of the leaf spring 126 from the clamping surface 122. Figure HA shows a plurality of holes 134 through clamping mechanism 120, a hole 134 per clamp finger 132. Figure 11B shows these holes 134 and most importantly, the plurality of push rods 136 extending to through the holes 134 from the rear side 136 of the clamp mechanism 120 to the clamping surface 122. What is not shown is a lever arm or other mechanism that simultaneously pushes the plurality of push rods 136 when the clamp mechanism 120 is instructed to disengage the clamp and move the probe 8. Figure 12 is an illustration of another embodiment alternative of the present invention. The vertically movable member 14 is shown having another shape that allows it to have placed two horizontally movable members 24 each having its own blade or associated saw blades 38. This embodiment allows the probe 8 to be cut simultaneously at different points in the medium circumferentially on the surface of the probe. This is especially useful for making cuts in probes that have multiple incisions, for example in diametrically opposed positions in the probeIt should be noted that even though the preferred embodiment has been defined as having a horizontally movable member with the spindle engaging the same for the saw blade, the positioning of the movable members vertically and horizontally can be changed. In this arrangement, the horizontally movable member engages in the base member, and the vertically movable member, and the vertically movable member has a spindle rotatably coupled thereto. An alternative embodiment of the present invention uses a lever arm that is capable of moving at least two degrees of freedom so that it can move vertically and horizontally to a position at the end of the spindle. Another aspect of the invention to be clarified is that rotating the probe is not limited to the use of a rotary clamping mechanism. For example, the clamp may be non-rotatable and disengage to allow the probe feeding mechanism to rotate the probe and then reattach the clamp to make additional incisions. In addition, the clamp and the probe feeding mechanism can be rotated together before additional incisions are made. Alternative aspects of the invention include the replacement of a non-mechanical cutting tool for the rotating blade of the currently preferred embodiment. For example, a laser can be provided to cut through the materials that are mounted in the system. It should also be understood that rotating backpacks are not just the type of mechanical blade that can be used. Conventional "saw" blades can also be provided. It should be understood that the embodiments described above are only illustrative of the application of the principles of the present invention. Numerous modifications and alternative arrangements can be devised by those skilled in the art without deviating from the spirit and scope of the present invention. The appended claims are intended to cover these modifications and provisions.