Portable hand held power tool with interchangeable head

Portable, hand held, battery operated, hydraulic tools are provided with a tool frame and one or more interchangeable working heads. When the working head is connected with the tool frame, a piston actuated by a hydraulic system within the tool frame applies force to the working head to perform a task. A coupling mechanism holds the working head to the tool frame. The coupling mechanism allows the working head to be removed from the tool frame and another working head to be joined to the tool frame. The coupling mechanism can hold the working head at a fixed rotational angle with respect to the tool frame. The coupling mechanism can also allow the working head to rotate with respect to the tool frame.

BACKGROUND

Field

The present disclosure relates to power tools and, more particularly, to portable, hand-held power tools with interchangeable heads.

Description of the Related Art

Portable, handheld power tools are used to perform a variety of tasks. Such tools include a power source such as a battery, an electric motor, and a working component, such as a saw, cutting blade, grinding wheel, or crimper. Some portable tools incorporate a hydraulic pump to drive a piston to apply a relatively large amount of force or pressure for a particular task. Some of these hydraulic tools include a working head with working surfaces shaped to perform a particular action on a workpiece, for example, crimping or cutting. Force from the piston actuated by the hydraulic system is applied to the workpiece to perform the desired task.

Battery powered hydraulic tools are employed in numerous applications to provide an operator with a desired flexibility and mechanical advantage. For example, an operator of a hydraulic power tool equipped with a head having a cutting blade can cut large conductors e.g., #8 conductors and larger. Likewise, an operator using a hydraulic tool equipped with a head including crimping surfaces can use the tool to make crimped connections on large conductors.

Many hydraulic tools require relatively expensive components to provide sufficient power, durability, and reliability for industrial and commercial tasks. Such tools may also require strong components to withstand significant forces required to perform industrial processes. Thus, such tools may be expensive, heavy, and bulky.

SUMMARY

The present disclosure provides exemplary embodiments of hydraulic power tools with a tool frame that can be connected with interchangeable heads. Such tools allow an operator to change the function of a single tool frame so the same tool frame can perform a variety of different tasks. This may reduce the expense required to equip the user because a single tool frame can be joined with different working heads to perform different tasks. Using interchangeable working heads on a single tool frame may also reduce the weight and bulk of the equipment a user must bring to the job site.

A tool according to the disclosure include a tool frame and a working head. The working head may include an impactor element that is driven by a hydraulic actuator on the tool frame and an anvil against which a workpiece is pressed as the impactor element is driven. Interchangeable heads with different impactors and anvils are provided for performing a variety of tasks, including crimping and cutting workpieces. In addition, the impactor and anvil of a working head may themselves be interchangeable to perform different functions or may support dies for shaping workpieces.

In one embodiment, a hand-held hydraulic tool includes a tool frame and an interchangeable working head configured with elements to perform a particular task, e.g., crimping a particular type of crimp to join electrical conductors. The tool frame includes a coupling mechanism for removably connecting the tool with the working head so that force delivered by a hydraulically driven piston of the tool actuates working surfaces of the head to perform the task. The working head includes structures to engage with a coupling mechanism on the tool frame and securely connect the head with the tool frame. To secure the working head to the tool frame, a locking mechanism may be provided that secures the coupling mechanism from inadvertently allowing the head to uncouple from the tool until the operator chooses to remove the head.

DETAILED DESCRIPTION

Illustrative embodiments of the present disclosure may be provided as improvements to portable, hand held, battery operated, hydraulic tools and one or more interchangeable working heads for performing different tasks.

FIGS. 1-4show an exemplary embodiment of a hydraulic power tool10according to the present disclosure. The tool10includes a tool frame12and a working head14. Within the frame12, and not shown here, is a battery driven hydraulic system. Such a system may comprise a pump, motor, fluid reservoir, controller and hydraulic drive conduit system. An exemplary embodiment of such a hydraulic system is shown in co-pending U.S. patent application Ser. No. 15/429,869, which issued as U.S. Pat. No. 10,109,971 on Oct. 23, 2018, and which is incorporated herein by reference. Battery20provides electrical power to the hydraulic system. Piston60is driven by the hydraulic system to provide force in the distal direction to the working head14. The tool frame12includes a main body30and a handle40that form a pistol-like shape. However, the tool frame12could be in any suitable type of shape.

The battery20is removably connected to the bottom of the handle40. In another embodiment, the battery20could be removably mounted or connected to any suitable position on the tool frame12. In another embodiment, the battery20may be affixed to the tool10so that it is not removable. The battery20is preferably a rechargeable battery, such as a lithium ion battery, that can output a voltage of at least 16 VDC, and preferably in the range of between about 16 VDC and about 24 VDC. In the exemplary embodiment shown inFIG. 1, the battery20can output a voltage of about 18 VDC.

The handle40includes one or more operator controls, such as trigger switches42and44, which can be manually activated by an operator. The handle40may include a hand guard46to protect an operator's hand while operating the tool10and to prevent unintended operation of trigger switches42and44. According to an embodiment of the present disclosure, one of the trigger switches (e.g., trigger switch42) may be used to pressurize hydraulic cylinder61to drive the piston60in the distal direction, as shown inFIG. 4, to deliver force to the working head to perform a task, such as crimping or cutting. The other trigger switch (e.g., trigger switch44) may be used to depressurize hydraulic cylinder61to retract the piston60in the proximal direction to the home position, shown inFIGS. 1 and 3.

As shown inFIG. 2, the working head14is separable from the main body30. The main body30includes a tool connecting portion32. Working head14includes a head connecting portion34. The tool connecting portion32includes a T-shaped slot36. The head connecting portion34includes upper and lower connecting arms38,39connected with a ring35. In operation, piston60provides force to a drive shaft50distally, as shown inFIG. 4, to deliver force to a workpiece. The connecting arms38,39are L-shaped, with upper extension40extending upward from the top connecting arm38and lower extension41extending downward from the lower connecting arm39. The cross section of the connecting arms38,39and extensions40,41correspond to the cross section of the T-shaped slot36so that when the head connecting portion34is aligned with the tool connecting portion32, the arms38,39and extensions40,41slide into the T-shaped slot36, as shown inFIG. 2.FIGS. 3 and 4show cross sectional views of the working head14connected with the main body30.

To prevent the working head14from inadvertently disconnecting from the main body30, a locking mechanism42is provided on the tool connecting portion32that engages a hole44on a top surface of extension40of connecting arm38of the head connecting portion34. As shown in cross section inFIGS. 3 and 4, the locking mechanism42includes a ball41within a blind hole45in contact with the lower end of a spring43. The upper end of the spring43contacts the closed end of the blind hole45. The diameter of the open end of the blind hole45is slightly smaller than the diameter of the ball41so the ball extends partway out of the hole45but remains captive in the hole45. The spring forces the ball41downward to extend partially from blind hole45. When the head14is engaged with the main body30, hole44on the head engagement portion34aligns with hole45of the tool engagement portion32. Ball41engages with hole44. Engagement of the ball41with hole44inhibits movement of the working head14in the direction of T-shaped slot36. To remove head14from main body30, sufficient force must be applied along the direction of T-shaped slot36to force the ball41upward against the force of spring43to disengage the ball41from hole44.

As shown inFIGS. 3 and 4, working head14includes drive shaft50and piston connector46. Piston connector46includes a T-shaped slot48. The axis of slot48is aligned with the axis of T-shaped slot36on the main body30. A groove62is provided near the distal end of the piston60. The distal end of the piston60thus forms a region with a T-shaped cross section. The T-shaped slot48of the piston connector46engages with the distal end of the piston60when the connecting arms38,39of the working head14are slid into T-shaped slot36. As shown inFIG. 4, motion of piston60in the distal direction is communicated to the working head14by the piston connector46and drive shaft50. As shown inFIG. 3, when the piston60returns to the home position, drive shaft50is retracted.

The drive shaft50connects with impactor52. The impactor52engages with a guide58on arm56. When the working head14is connected to the main body30and the piston60is driven in the distal direction, drive shaft50forces the impactor52along guide58, as shown inFIG. 4. Arm56is connected at its proximal end with the ring35. At its distal end, arm56supports an anvil surface54. When a workpiece is placed between the impactor52and anvil surface54and the piston50is driven in the distal direction, the impactor52and anvil54deform the workpiece, for example, to install a crimp or to cut the workpiece.

Force applied by the piston60to the head14is resisted by a reaction force between the distal surfaces of extensions40,41on the head14and proximal surfaces of the T-shaped slot36on the main body30that abut extensions40,41. In the embodiment shown inFIGS. 1-4, the T-shaped slot36engages the distal surfaces of extensions40and41in a plane perpendicular to the axis of the piston. Thus, the reaction force of the head14in response to the driving force of the piston60is normal to the plane where the arms40,41contact the T-shaped slot36. According to another embodiment, the distal-facing surfaces of extensions40,41and the corresponding proximal-facing surfaces of the T-shaped slot36are at an angle oblique to the axis of the piston. According to one aspect, the oblique angle of the distal-facing surfaces of extensions40and41is in the distal direction with respect to the axis of the piston to reduce a tendency of the top and bottom of the T-shaped slot36to splaying outward in response to the reaction force when force is applied to the head14by piston60.

According to the embodiment shown inFIGS. 1-4, the impacting tool52and anvil54are shaped to deform a workpiece into a substantially circular cross section, for example, to install a crimp connector joining two connectors. According to further embodiments, the impactor52and anvil54may be formed in a variety of shapes and configured for other tasks, for example, to provide a cutter for cutting a workpiece, or to hold dies to shape a workpiece.

Tool connecting portion32is rotatable with respect to main body30. Internal threads33are provided on the proximal inside surface of connecting portion32. These threads engage with threads on the distal outer surface of hydraulic cylinder61. During assembly, threaded portion33of tool connecting portion32is threaded onto the hydraulic cylinder61. Set screw59is then installed in a threaded hole near the proximal end of tool connecting portion32. A stop63is provided on the outer surface of hydraulic cylinder61. When set screw59is installed in connecting portion32, the set screw allows connecting portion32to rotate almost one complete rotation with respect to cylinder61before encountering the stop. This prevents tool connecting portion32from unscrewing from cylinder61.

According to the embodiment ofFIGS. 1-4, the tool connector portion32and head connector portion34have a circular profile. According to another embodiment, the profile of the connector portions32,34can be square, rectangular or other shape.

FIGS. 5-8show another embodiment according to the disclosure. Hydraulic power tool210includes a tool frame212, handle240, and battery driven hydraulic system similar to the embodiment described with respect toFIGS. 1-4. Working head214removably connects with the main body230so that different working heads214can be interchangeably connected with the frame212.

As shown inFIG. 6, tool210includes a tool connecting portion232. The tool connecting portion232has a slidable collar240surrounding an engagement cylinder250. Working head214includes a head connecting portion234that has an engagement ring236. The ring236of head214has a circumferential groove238on its outer surface. As shown inFIG. 8, when the working head214is connected with the main body230, piston260extends from the tool210through the ring236. Force applied to the piston260by the hydraulic system actuates portions of the working head214to perform work on a workpiece.

FIG. 7shows a cross section of the tool connecting portion232in relation to working head214. The collar240includes a shoulder244along its inside circumference near the proximal end of the collar240. Another shoulder246is provided on the main body230. A biasing spring242is positioned between shoulders244and246. InFIG. 7, the spring242is show in a compressed state with the collar240pulled in the proximal direction as shown by the arrow. A widened inner diameter portion248of the collar240is formed along the inside circumference of the collar240near its distal end.

The collar240surrounds the engagement cylinder250. Cylinder250has an inner diameter slightly larger than the outer diameter of the ring236on the working head214to form a clearance fit with ring236. Holes252are formed through the wall of the cylinder250. Balls254are located within the holes252. The diameter of the balls254is larger than the thickness of the cylinder250. The diameter of the holes252on the inside surface of cylinder250is slightly less than the diameter of the balls254so the balls can protrude from the holes into the interior of cylinder but remain captive in the holes.

When the collar240is pulled in the proximal direction, as shown inFIG. 7, the widened portion of the collar248is positioned adjacent the holes252, allowing the balls254to move away from the inner bore of the cylinder250.

Working head214is connected with the main body230as follows. Collar240is pulled proximally, as shown inFIG. 7. The ring236of the working head214is inserted into the cylinder250. The balls254are displaced away from interior of the cylinder250by the ring236and extend outward of the cylinder into the widened inner diameter portion248on the inside surface of the collar240. This allows the proximal end of the ring to pass the holes252and contact a stop256. As shown inFIG. 8, once the ring236is inserted fully against stop256in the cylinder250, collar240is allowed to move distally by the force exerted by spring242. The widened portion248along the inner diameter of the collar240is moved distal of the balls254so that the inner surface of the collar240presses the balls into the holes252. The balls254extend into the groove238on the ring236. Engagement of the balls254with the groove238locks the working head214to the cylinder250. According to one aspect of the embodiment, engagement of balls254with groove238allows the head214to rotate with respect to the main body230about the axis of the piston260.

To remove the working head214from the main body230, collar240is pulled proximally to the position shown inFIG. 7. This aligns the widened portion248with the holes252, allowing the balls254to move away from the groove238. The working head214is then be pulled away from the main body230and removed.

FIGS. 9-13show yet another embodiment of the disclosure. Tool310includes frame312, handle340, working head314, main body330, and hydraulic system similar to the embodiment described with respect toFIGS. 1-4. As shown inFIG. 10, at the distal end of the main body330is a tool connector portion332. At the proximal end of the working head314is head connector portion334.

Tool connector portion332includes rotatable collar340disposed around engagement cylinder350. Extending through holes in the side of the cylinder350are pins354a-d.FIG. 11is a cross section of interconnected tool engagement portion332and head engagement portion334in the plane of collar340showing pins354a-d.FIG. 13shows a cross section of the head314engaged with the main body330in a plane along the axis of the piston360. Each of the pins354a-dhas a groove356a-dnear the end of the pin extending out from cylinder350. As shown in the cross section ofFIG. 13, the slots358a-dof collar340have a narrow portion that engages with grooves356a-don each respective pin354a-d. As shown inFIG. 11, slots358a-dare angled with respect to the axis of rotation of the collar. The point where slots358a-dengage respective pins354a-dmoves radially with respect to the cylinder350when the collar340is rotated. Rotating the collar340counter clockwise pulls the pins354a-daway from the cylinder350and rotating the collar340clockwise pushes the pins354a-dtoward the cylinder350.

As shown inFIG. 13, a torsion spring343is positioned proximal of the collar340. One end of the spring is fixed to collar340and the other end is fixed to shoulder346of the main body330. A stop344is provided on cylinder350distal of the collar340. The torsion spring biases the collar to rotate in the clockwise direction so that, when no external rotational force is applied, collar340forces pins354a-dinward of the cylinder to lock the head with the frame, as will be explained below. An interlock (not shown) may be provided on the main body adjacent to the rotatable collar340. The interlock includes a switch that disables operation of the hydraulic system of the tool when the pins354a-dare not in their fully locked position. The interlock enables operation of the hydraulic system when the pins are fully engaged, assuring that the head314is securely connected with the main body330when the tool is operated.

As shown inFIG. 10, the head engagement portion334includes ring336. Holes338a-dare provided on ring336(only two of the holes are visible inFIG. 10). Along the top surface of ring336is a groove341parallel with the axis of the ring. Ridge342, shaped to fit into groove341, is provided along the top of the inner surface of cylinder350along the axis of the cylinder. When the groove341and ridge342are engaged, the holes338a-dare radially aligned with the positions of pins354a-dextending through cylinder350.FIG. 11shows the pins354a-dengaged with respective holes338a-d.

To connect the working head314with the main body330, a user rotates collar340counter-clockwise against the biasing force of torsion spring343. Engagement of the pins354a-dwith slots358a-don the collar causes the pins to withdraw from the interior of the cylinder350. Ring336is inserted into cylinder350with groove341aligned with ridge342. The engagement of the ridge341and groove342assures that the head314is aligned with the main body330and prevents the head from rotating relative to the main body350.FIG. 13shows the ring336fully inserted into the cylinder350with the proximal end of the ring336in contact with stop351. The user then releases collar340, allowing the bias force of spring343to rotate the collar clockwise so that pins354a-dare driven radially inward to engage with holes338a-d, thus securing the head314to the main body330. Torsion force applied by the spring keeps the pins engaged with the holes until the user applies a counter-clockwise force.

According to one embodiment, a detent mechanism is also provided to keep the collar340in a position where the pins354a-dremain engaged with holed358a-d. Such a mechanism may be formed by shaping slots358a-dto provide an “over center” engagement with pins354a-dso that rotation of the collar340presses the pins inward past a maximal point of insertion. To secure the head with the frame, the user applies a rotational force in the clockwise direction to turn collar240past the “over center” detent point to secure the pins into engagement with holes in the ring.

As shown inFIG. 13, a drive shaft362extends through ring336of the head314. A hydraulic cylinder361is provided within the main body330to drive piston360. A drive shaft engagement346connects the piston360with the drive shaft362. According to one aspect, the engagement mechanism346is provided by a friction fit between a hole at the proximal end of the drive shaft362and pliant material, such as a neoprene o-ring, on the distal end of the piston360. Driving force is communicated from the piston360to the drive shaft362in the distal direction by contact between the distal end of the piston and the proximal end of the drive shaft within the engagement mechanism. The friction fit of the pliant material provides traction between the drive shaft362and the piston360to pull the drive shaft back to the home position. According to another embodiment, instead of or in addition to a frictional engagement, drive shaft362and piston360may be coupled by a magnetic coupling.

To remove head314from the main body330, collar340is rotated counterclockwise against the torsional force of spring343so that pins354a-dare withdrawn from holes338a-d. Head314is then pulled away from the main body330, pulling the ring336out of the cylinder350and overcoming the friction fit of engagement mechanism346and piston360.

FIG. 12shows an alternative embodiment of the mechanism shown inFIG. 11. Pins354a-dextend through holes in collar350similar to the arrangement described with respect toFIG. 11. In this embodiment, springs355a-dare disposed around the pins354a-dbetween the heads of the pins357a-dand the outer surface of cylinder350. The springs355a-dprovide a biasing force pulling the pins radially outward from the cylinder350. Slots359a-dare provided on the inner surface of collar340. When the collar340is rotated so that the heads of the pins357a-dare aligned with the slots359a-d, the pins are pulled radially outward by the bias force of the springs355a-d. As with the embodiment described in regard toFIG. 11, to connect a head314with the main body330, collar240is rotated so that pins354a-dare withdrawn from the inside of the cylinder350. The ring336of the head314is inserted into the cylinder350. The collar340is rotated so that slots359ad-dare rotated away from pins354a-dcausing the inside surface of the collar340to contact the heads357a-dof the pins to push the pins inward, as shown inFIG. 12. Pins354a-dextend inward of cylinder350and engage with holes338a-don the ring336locking the head314to the main body330.

Embodiments described with regard toFIGS. 9-13prevent the head314from rotating with respect to the main body330. Rotation is prevented by both the engagement of ridge342and groove341on the cylinder350and ring336, respectively, and by engagement of pins354a-dand holes338a-d.

FIGS. 14-18show a further embodiment of the disclosure that provides a mechanism for locking an interchangeable working head414with the main body430of a tool410. Tool410includes frame412, handle440, working head414, main body430, and hydraulic system similar to the embodiments described above. As shown inFIG. 15, at the distal end of the main body430is a tool connector portion432. At the proximal end of the working head414is head connector portion434.

Tool connector portion432includes rotatable collar440disposed around engagement cylinder450. Extending through holes in the side of the cylinder450are one or more pins454a-d.FIG. 16shows a cross section of the interconnected tool engagement portion432and head engagement portion434in the plane of collar440.FIG. 18shows a cross section of the head414engaged with the main body430in a plane parallel to the axis of piston460. In this embodiment, four pins454a-dare provided around the cylinder450. Each of the pins454a-dhas extensions456near the end of the pin extending out from cylinder450, as shown inFIG. 17. Rotatable collar440includes slots458a-dthat engage with extensions456on respective pins454a-d. As shown inFIG. 16, slots458a-dare angled with respect to the axis of rotation of the collar so that when the collar440is rotated, the point where the extensions456on each of the pins454a-dengages its respective groove moves radially with respect to the cylinder450. Rotation of the collar in the counter clockwise direction pulls pins454a-daway from cylinder450. Rotation of the collar in the clockwise direction pushes the pins inward toward the cylinder450. In an alternative embodiment, slots458a-dare in the form of threads that extend partially or fully around a circumference of collar440. Extensions456on the pins are curved to match the pitch of the groove or thread.

The head engagement portion434of head414includes engagement ring436. A groove438is provided around the circumference of the ring436. As shown inFIG. 17, groove438is shaped to accept insertion of pins454a-dwhen the pins are extended inward of the cylinder450.

As shown inFIG. 18, torsion spring443is fixed at its distal end with collar440and at its proximal end with main body430. As with the previous embodiment, torsion spring443biases the collar440in the clockwise direction so that when no rotational force is applied to the collar, pins454a-dare pushed inward of cylinder450.

To connect the working head414with the main body430, a user rotates collar440counterclockwise against the biasing force of spring443so that pins454a-dare withdrawn from the interior of the cylinder450. The ring436of the head414is inserted into the cylinder450.FIG. 18shows the ring436fully inserted into the cylinder450with the proximal end of the ring436in contact with stop451. The user then releases the collar, which is driven clockwise by spring443. Pins454a-dare driven radially inward so that they engage with the groove438, thus securing the head414to the main body430. Because groove438is continuous about the ring436, the head414can rotate with respect to the main body430. As with the embodiment ofFIGS. 9-13, drive shaft462is connected with piston460of the main body430by a drive shaft engagement446, which may be a friction fit connection.

To remove head414from the main body430, the user rotates collar440counter-clockwise so that pins454a-dare withdrawn from engagement with groove438. The user pulls head414away from the main body430, pulling the ring436out of the cylinder450.

FIGS. 19-21show another embodiment of the disclosure. Tool510includes frame512, handle540, working head514, main body530, and hydraulic system similar to the embodiments described above. As shown inFIG. 20, the distal end of the main body530includes tool connector portion532. At the proximal end of the working head514includes head connector portion534.

Tool connector portion532includes rotatable collar540disposed around engagement cylinder550. As shown in the cross section inFIG. 21, collar540includes extensions554a-d. Cylinder550includes slots552a-d. Extensions554a-dextend through corresponding slots552a-dinto the interior of cylinder550.

As shown inFIG. 20, head engagement portion534includes ring536. Ridges538a-dare formed on the surface of ring536. In the view shown inFIG. 20, only two of the ridges are visible. Ridges538a-dinclude respective notches542a-d. Between the ridges538a-dare relieved areas541a-d. The diameter of the head connecting portion534in the area of the ridges538a-dis slightly less than the inner diameter of cylinder550. This allows head connecting portion534to be inserted into the cylinder550of the tool connecting portion with a small amount of clearance between the ridges538a-dand the inside of the cylinder550.

As shown inFIG. 21, when head514is connected with main body530, the inward pointing ends of the extensions554a-dof collar540are disposed in corresponding notches542a-dof head514. Engagement of extensions554a-dwith notches542a-dprevents ring536from moving distally with respect to cylinder550, thus locking head514to the main body530.

To connect the working head514with the main body530, collar540is rotated clockwise so that extensions554a-dalign with relieved portions541a-dof ring536. This allows ridges538a-dto pass between extensions554a-d. Ring536of the head514is inserted into the cylinder550of the main body530. When the ring536is fully inserted into cylinder550, the proximal end of ring536abuts a stop (not shown) at the proximal end of the cylinder. In this configuration, notches542a-dare aligned with extensions554a-d. Collar540is then rotated counter clockwise so that extensions554a-dare moved into respective slots542a-d, as shown in the cross section ofFIG. 21.

To remove head514from the main body530, collar540is rotated in a clockwise direction so that extensions554a-dare moved out from notches542a-dand aligned with relieved portions541a-d. The head514is pulled away from the main body530, pulling the ring536out of the cylinder550.

FIGS. 22-24show another embodiment of the disclosure. Tool610includes frame612, handle640, working head614, main body630, and hydraulic system similar to the embodiments described above. As shown inFIG. 23, the distal end of the main body630includes tool connector portion632. At the proximal end of the working head614is head connector portion634.

As shown inFIG. 23, head engagement portion634includes a ring636. Arms638a-dextend in the proximal direction from the ring. At the proximal end of each arm is an extension640a-dfacing radially outward from the ring636. The outer diameter of ring636and arms638a-dis slightly less than the inner diameter of cylinder650so that a clearance fit is provide between the ring and cylinder. Tool connector portion632includes an engagement cylinder650. The outer diameter of extensions640a-dis larger than the inner diameter of cylinder650. Notches654a-dare provided on the interior surface of cylinder650.

As shown inFIG. 24, when head614is connected with main body630, extensions640a-dare disposed in corresponding notches654a-d. Engagement of extensions640a-dwith notches654a-dprevents ring636from moving or rotating with respect to cylinder650, thus locking head614to the main body630.

According to an alternative embodiment, instead of discrete notches654a-d, a continuous groove extends around the inner surface of cylinder650. The groove is shaped to engage with extensions640a-d. An aspect of this embodiment is that the head614is fixed to the main body630, but can rotate about the axis of the piston.

To connect the working head614with the main body630, arms638a-don ring636are compressed radially inward so that extensions640a-dfit within the cylinder650. Arms640a-deach may include a sloped region on its proximal surface that engages the distal lip of the cylinder650to push the arms radially inward as the arms are forced into the cylinder. The ring636is pushed into cylinder650and adjusted so that extensions640a-dalign with respective notches654a-d. Recoil from the compressed arms638a-dpushes extensions638a-dradially outward into notches654a-d, thus locking head614with main body630. Arms638a-dalso include a sloped region639a-don their proximal sides. To remove the head614from the main body630, the head is pulled in the distal direction. Sloped regions639a-dengage with the distal edges of notches654a-dand the sloped region exerts a radially directed inward force as the sloped region639a-drides up the distal edges of the notches until the arms are free of the notches. Ring636can then be pulled out of cylinder650and the head614separated from the main body630.

As shown throughout the drawings, like reference numerals designate like or corresponding parts. While illustrative embodiments of the present disclosure have been described and illustrated above, it should be understood that these are exemplary of the disclosure and are not to be considered as limiting. Additions, deletions, substitutions, and other modifications can be made without departing from the spirit or scope of the present disclosure. Accordingly, the present disclosure is not to be considered as limited by the foregoing description.