HK1069142B - Adjustable length punch assembly - Google Patents

Description

Length-adjustable punching assembly

Technical Field

The present invention generally relates to metal working tools. In particular, the present invention relates to a punch assembly for use in a punch press.

Background

Metal sheets can be economically processed into many useful products, including chassis for equipment and appliances. Vertical or turret punch presses have been widely used in the processing of metal sheets. Turret punch presses employ a generally cylindrical upper turret that holds a series of circumferentially spaced punch tools around its periphery and a lower turret that holds a series of circumferentially spaced dies around the periphery of the turret, each turret being rotatable about a vertical axis to vertically align the appropriate punch and die pairs in the operative position. By appropriately rotating the two turrets, the operator can sequentially align a plurality of punches and dies at the work position to perform a series of successive and distinct punching operations on the workpiece.

Repeated use of the punch assembly during operation of the punch press results in the punch tip becoming naturally dull and worn. Once the tip has become blunt, the effectiveness of the punch assembly is reduced and the punch tip must be sharpened. Sharpening may be achieved by grinding the end of the punch tip, which results in a shorter punch length. The length of the punch can then be adjusted to compensate for the worn out portion.

The longitudinal length of the punch assembly is typically disposed in coaxial alignment with the axis of the ram. The ram of the press then impacts the punch with great force on its impact surface.

US 5,647,256 a discloses a punch unit with an adjustable punch, but it has the disadvantages of poor reliability, low accuracy, short life and not being able to meet the requirements of different conditions of use well.

Disclosure of Invention

The present invention generally relates to metal working tools. More particularly, the present invention relates to a length adjustable punch assembly for use in a punch press having a ram, the punch assembly comprising: a punch body assembly configured for threaded engagement with a drive body assembly having an impact surface adapted to be impacted by a ram of a punch press, the punch assembly being adjustable in length with respect to one body for rotation relative to the other body about a longitudinal axis of the punch assembly; a locking mechanism for selectively preventing rotation of the punch body assembly relative to the drive body assembly; said locking mechanism including a lock shaft connected to one of the bodies and a lock key slidably connected to the other body so as to be slidable along a lock key channel, wherein said lock key includes an opening adapted to receive said lock shaft, the opening extending about the longitudinal axis and including a shaft engaging portion facing the longitudinal axis; and the keying channel is disposed at an angle relative to the longitudinal axis of the punch assembly.

In some embodiments of the invention, the angle between the keyway and the longitudinal axis of the punch body assembly is a right angle. In other embodiments, the angle between the detent channel and the longitudinal axis of the punch body assembly is acute. In some embodiments, the catch channel is substantially parallel to the impact surface of the drive body assembly.

In one aspect of the invention, the catch is movable between a first position in which the catch engages the latch shaft and a second position in which the catch is disengaged from the latch shaft. The adjustable length punch assembly may advantageously include a means for biasing the catch toward the first position. In one embodiment of the invention, the means for biasing the locking key toward the first position comprises a spring having a first end seated against the locking key and a second end seated against one of the bodies.

In one aspect of the invention, the lock shaft has a first axial degree of freedom relative to the lock key. In a preferred embodiment of the invention, the first axial degree of freedom is substantially parallel to the longitudinal axis of the punch assembly.

In one embodiment of the invention, the shaft-engaging portion of the locking key preferably includes at least one tooth. In other embodiments, the shaft-engaging portion of the detent preferably includes at least one flat surface.

Drawings

FIG. 1 is a cross-sectional view of a punch assembly according to an exemplary embodiment of the present invention;

FIG. 2 is an enlarged plan view of the punch assembly of FIG. 1;

FIG. 3 is another enlarged plan view of the punch assembly of FIGS. 1 and 2;

FIG. 4 is a perspective view of a lock shaft of the adjustable length punch assembly of FIGS. 1, 2 and 3;

FIG. 5 is a plan view of a length adjustable punch assembly according to another embodiment of the present invention;

FIG. 6 is another plan view of the adjustable length punch assembly of FIG. 5; and

fig. 7 is a cross-sectional view of a punch assembly according to another exemplary embodiment of the present invention.

Detailed Description

The following detailed description should be read with reference to the drawings, in which like elements are numbered alike. The drawings, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. Examples of structures, materials, dimensions, and fabrication processes are provided for selected elements. All other elements are well known to those skilled in the art. One of ordinary skill in the art will recognize that many of the embodiments provided have suitable alternatives that may be utilized.

Fig. 1 is a cross-sectional view of a punch kit 100 according to an exemplary embodiment of the present invention. The punch kit 100 includes a sleeve 104 and an adjustable length punch assembly 102 slidably disposed within the sleeve 104. The stamping kit 100 may be used in a press that includes a fixture 108 adapted to receive the sleeve 104 and a ram 120 adapted to move longitudinally along a ram axis 122.

In the embodiment of fig. 1, the adjustable length punch assembly 102 includes a punch body assembly (or punch body assembly) 124 configured to threadably engage a drive body assembly 126 having an impact surface 128 adapted to be impacted by a ram 120 of a punch press. The adjustable length punch assembly 102 may be adjusted in length by rotating the punch body assembly 124 and the drive body assembly 126 relative to each other.

The punch body assembly 124 includes a punch 130, an externally threaded member 132 and a lock shaft 134. As shown in fig. 1, the externally threaded member 132 is attached to the die cutter 130 by a relatively large cap screw 136 that is axially threaded into a threaded bore in the die cutter 130. Also as shown in fig. 1, a plurality of pins 138 and a fixing ring are used to connect the lock shaft 134 to the externally threaded member 132.

The drive body assembly 126 of fig. 1 includes a drive cap 144 and an internally threaded member 146. In the embodiment of FIG. 1, the drive cap 144 is coupled to the internally threaded member 146 by a plurality of cap screws 140, one of the cap screws 140 being shown in FIG. 1. As can be appreciated in fig. 1, the internally threaded member 146 of the drive body assembly 126 is disposed in threaded contact with the externally threaded member 132 of the punch body assembly 124.

As described above, the length of the adjustable length punch assembly 102 may be adjusted by rotating the punch body assembly 124 and the drive body assembly 126 relative to each other. In the embodiment of fig. 1, adjustable length punch assembly 102 includes a locking mechanism 150 for selectively preventing punch body assembly 124 from rotating relative to drive body assembly 126. The locking mechanism 150 of fig. 1 includes the latch shaft 134 of the punch body assembly 124 and a latch 148, the latch 148 slidably engaging the drive cap 144 of the drive body assembly 126 such that the latch 148 is slidable along a latch channel 152.

In the embodiment of fig. 1, the channel through which catch 148 is utilized is defined in part by guide surface 154 of drive cap 144 of drive body assembly 126. In fig. 1, it will be appreciated that the detent channel 152 is disposed at an angle a relative to a longitudinal axis 156 of the adjustable length punch assembly 102. It will also be appreciated in fig. 1 that the detent channel 152 is disposed at an angle B relative to the ram axis 122 of the ram 120 when the adjustable length punch assembly 102 is received by the clamp 108. In a preferred embodiment, the adjustable length punch assembly 102 and ram 120 are disposed in a generally coaxial relationship during punching.

In the embodiment of fig. 1, both the angle a between the catch channel and the longitudinal axis 156 and the angle B between the catch channel 152 and the ram axis 122 are right angles. This may also be the case for embodiments of the present invention in which both included angle a and included angle B are acute or obtuse angles. In the embodiment of fig. 1, it may be noted that detent channel 152 is substantially parallel to impact surface 128 of drive body assembly 126.

Latch shaft 134 has a first axial degree of freedom relative to latch key 148. In the embodiment of fig. 1, latch shaft 134 is free to move along longitudinal axis 156 relative to latch 148. This axial degree of freedom enables the length of the adjustable length punch assembly 102 to be adjusted.

The punch set 100 also includes a spring assembly 158 that includes a plurality of belleville washers 160. A first end of spring assembly 158 seats against drive cap 144 of drive body assembly 126. The second end of spring assembly 158 seats against spring support ring 162. Spring support ring 162 in turn seats against flange 164 of sleeve 104.

During a stamping operation, the ram 120 impacts downwardly on the impact surface 128 of the drive body assembly 126, compressing the spring assembly 158 and forcing the adjustable length punch assembly 102 downwardly until the die blade 130 extends below the lower surface 166 of the stripper plate 168 of the punch assembly 100. The extended die 130 is passed through a workpiece (not shown) to punch an article having a desired shape from the workpiece. The punch assembly 100 may employ various die shapes and mating stripper plates depending on the shape to be removed from the workpiece.

The ram 120 may then be retracted, thereby releasing the compressive force on the spring assembly 158. As the die 130 retracts upward through the stripper plate 168, its sides will engage the workpiece, which is often attached to the retracted die 130. The stripper plate 168 may engage the top surface of the workpiece to help separate it from the die 130.

Repeated use of the die cutter in the operation of the press results in the die cutter becoming naturally dull and worn. Once the die cutter has become dull, the effectiveness of the punch assembly is reduced and the die cutter must be sharpened. Sharpening can be achieved by grinding the end of the punch tip, which results in a shorter length of the punch. The length of the punch assembly may then be adjusted to compensate for the worn out portion of the die cutter.

Typically, when sharpening of the die cutter 130 is required, the operator removes the die cutter 130 from the stamped kit 100, for example, by loosening the larger cap screw 136. The die 130 may then be sharpened or replaced. After replacing or sharpening the punch 130, appropriate changes in the overall length of the adjustable length punch assembly 102 may be made by rotating the punch body assembly 124 and the drive body assembly 126 relative to each other. The catch 148 of the locking mechanism 150 selectively engages the latch shaft 134 to prevent inadvertent changes in the length of the adjustable length punch assembly 102. The possibility of a length change may occur due to a reduction in the force of the ram 120 impacting the adjustable length punch assembly 102 when the detent channel 152 of the detent 148 is disposed at an angle to the ram axis 122.

Fig. 2 is an enlarged plan view of the stamped kit 100 of fig. 1. As can be seen in FIG. 2, lock shaft 134 includes a plurality of teeth 170. In fig. 2, it can also be seen that catch 148 includes an opening 174 adapted to receive latch shaft 134. Catch 148 is preferably movable between a first position in which catch 148 engages latch shaft 134 and a second position in which the catch is disengaged from latch shaft 134. In the embodiment of fig. 2, catch 148 is shown in a first position.

The adjustable length punch assembly 102 of the punch assembly 100 preferably includes a mechanism for biasing the catch 148 toward the first position. In the embodiment of fig. 2, adjustable length punch assembly 102 includes a spring 176 having a first end seated against a first seating surface 178 of catch 148 and a second end seated against a second seating surface 180 of drive cap 144 of drive body assembly 126.

Fig. 3 is another enlarged plan view of the stamping kit 100 of fig. 1 and 2. As previously described, catch 148 is preferably movable between a first position wherein catch 148 engages latch shaft 134 and a second position wherein the catch is disengaged from latch shaft 134. In the embodiment of fig. 2, catch 148 is shown in a first position. In the embodiment of fig. 3, a force F is shown acting on the catch 148 and forcing it into the second position. The spring 176 preferably biases the lock key 148 toward the first position.

In fig. 3, it can be seen that the opening 174 of the catch 148 is partially defined by the shaft engaging portion 182 of the catch 148. In the embodiment of fig. 3, the shaft-engaging portion 182 of the catch 148 includes a plurality of mating teeth 172. Mating teeth 172 are preferably configured to intermesh with teeth 170 of lock shaft 134. It is to be understood that other embodiments of the shaft engaging portion 182 are possible without departing from the spirit and scope of the present invention.

Fig. 4 is a perspective view of the lock shaft 134 of the adjustable length punch assembly 102. As can be seen in FIG. 4, lock shaft 134 includes a plurality of holes 184. The holes 184 are preferably adapted to receive screws, pins or other fasteners for attaching the lock shaft 134 to the externally threaded member 132 of the punch body assembly 124. Also shown in fig. 4 is tooth 170 of lock shaft 134.

Fig. 5 is a plan view of an adjustable length punch assembly 202 according to another embodiment of the present invention. The adjustable length punch assembly 202 of fig. 5 includes a drive body assembly 226 having a drive cap 244 and a punch body assembly 224 having a lock shaft 234. As in the previous embodiment, the punch body assembly 224 is preferably configured to threadably engage the drive body assembly 226. The length of the adjustable length punch assembly 202 may be adjusted by rotating the punch body assembly 224 and the drive body assembly 226 relative to each other.

In the embodiment of fig. 5, latch shaft 234 and latch 248 of punch body assembly 224 form part of a locking mechanism 250 for preventing punch body assembly 224 from rotating relative to drive body assembly 226. The catch 248 slidably engages the drive cap 244 of the drive body assembly 226 such that the catch 248 slides along a catch channel. In fig. 5, it can be seen that the latching tab 248 includes an opening 274 for receiving the latch shaft 234. Detent 248 is preferably movable between a first position in which detent 248 engages detent shaft 234 and a second position in which detent is disengaged from detent shaft 234. In the embodiment of fig. 5, catch 248 is shown in a first position.

The adjustable length punch assembly 202 preferably includes a mechanism for biasing the catch 248 toward the first position. In the embodiment of fig. 5, adjustable length punch assembly 202 includes a spring 276 having a first end seated against a first seating surface 278 of catch 248 and a second end seated against a second seating surface 280 of drive cap 244 of drive body assembly 226.

FIG. 6 is another enlarged plan view of the adjustable length punch assembly 202 of FIG. 5. As previously mentioned, catch 248 is preferably movable between a first position wherein catch 248 engages latch shaft 234 and a second position wherein catch is disengaged from latch shaft 234. In the embodiment of fig. 6, a force F is shown acting on the catch 248 and forcing it into the second position.

As can be seen in fig. 6, the opening 274 of the catch 248 is partially defined by the shaft-engaging portion 282 of the catch 248. In the embodiment of fig. 5, the shaft-engaging portion 282 of the catch 248 includes a plurality of mating flats or flats 288. Further, in the embodiment of fig. 5, mating flats 288 are substantially similar in size and shape to flats 286 of lock shaft 234.

Fig. 7 is a cross-sectional view of a stamping kit assembly 300 according to another exemplary embodiment of the invention. The punch set 300 includes a sleeve 304 and an adjustable length punch assembly 302 slidably disposed within the sleeve 304. In the embodiment of fig. 7, adjustable length punch assembly 302 includes a punch body assembly 324 configured for threaded engagement with a drive body assembly 326 having an impact surface 328 adapted to be impacted by a ram of a punch press.

The punch body assembly 324 includes a punch 330, an externally threaded member 332, and a lock shaft 334. As shown in fig. 7, the externally threaded member 332 is attached to the die cutter 330 by a relatively large cap screw 336 that is axially threaded into a threaded bore in the die cutter 330. Further, as shown in fig. 7, the lock shaft 334 is coupled to the externally threaded member 332 using a plurality of screws 338.

Drive body assembly 326 of FIG. 7 includes a drive cap 344 and an internally threaded member 346. In the embodiment of fig. 7, the driver cap 344 is attached to the internally threaded member 346 by a plurality of cap screws 340, one of the cap screws 340 being shown in fig. 7. As can be seen in fig. 7, the internally threaded member 346 of the drive body assembly 326 is disposed in threaded contact with the externally threaded member of the punch body assembly 324.

The press set 300 also includes a spring assembly 358 that includes a plurality of belleville washers 360. The first end of spring assembly 358 is seated against drive cap 344 of drive body assembly 326. The second end of the spring assembly 358 seats against the spring support ring 362. The spring support ring 362 in turn seats against a flange 364 of the sleeve 304.

The length of the adjustable length punch assembly 302 may be adjusted by rotating the punch body assembly 324 and the drive body assembly 326 relative to each other. In the embodiment of fig. 7, adjustable length punch assembly 302 includes a locking mechanism 350 for selectively preventing punch body assembly 324 from rotating relative to drive body assembly 326. The locking mechanism 350 of fig. 7 includes a lock shaft 334 of the punch body assembly 324 and a lock key 348, the lock key 348 slidably engaging the drive cap 344 of the drive body assembly 326 such that the lock key 348 is slidable along a lock key channel 352.

In the embodiment of fig. 7, the passageway through which catch 348 is utilized is defined in part by guide surface 354 of drive cap 344 of drive body assembly 326. As can be seen in fig. 7, the detent channel 352 is disposed at an angle C relative to the longitudinal axis 356 of the adjustable length punch assembly 302. In the embodiment of fig. 7, the angle C between detent channel 352 and longitudinal axis 356 is acute.

Several forms of the invention have been shown and described, and other forms will be apparent to those skilled in the art. It is to be understood that the embodiments shown in the drawings and described above are merely for illustration and are not meant to limit the scope of the invention.

Claims (15)

1. An adjustable length punch assembly for use in a punch press having a ram, the punch assembly comprising:

a punch body assembly configured for threaded engagement with a drive body assembly having an impact surface adapted to be impacted by a ram of a punch press, the punch assembly being adjustable in length with respect to one body for rotation relative to the other body about a longitudinal axis of the punch assembly;

a locking mechanism for selectively preventing rotation of the punch body assembly relative to the drive body assembly;

said locking mechanism including a lock shaft connected to one of the bodies and a lock key slidably connected to the other body so as to be slidable along a lock key channel, wherein said lock key includes an opening adapted to receive said lock shaft, the opening extending about the longitudinal axis and including a shaft engaging portion facing the longitudinal axis; and

the detent channel is disposed at an angle relative to a longitudinal axis of the punch assembly.

2. The adjustable length punch assembly of claim 1, wherein the angle between the detent channel and the longitudinal axis of the punch body assembly is a right angle.

3. The adjustable length punch assembly of claim 1, wherein the angle between the detent channel and the longitudinal axis of the punch body assembly is acute.

4. The adjustable length punch assembly of claim 1, wherein the detent channel is substantially parallel to the impact surface of the drive body assembly.

5. The adjustable length punch assembly of claim 1, wherein the catch is movable between a first position in which the catch is engaged with the lock shaft and a second position in which the catch is disengaged from the lock shaft.

6. The adjustable length punch assembly of claim 5, further comprising a means for biasing the catch toward the first position.

7. The adjustable length punch assembly of claim 6, wherein the means for biasing the catch toward the first position comprises a spring having a first end seated against the catch and a second end seated against one of the bodies.

8. The adjustable length punch assembly of claim 1, wherein the lock shaft has a first axial degree of freedom relative to the lock key.

9. The adjustable length punch assembly of claim 8, wherein the first axial degree of freedom is substantially parallel to a longitudinal axis of the punch assembly.

10. The adjustable length punch assembly of claim 1, wherein the shaft engaging portion of the detent comprises at least one tooth.

11. The adjustable length punch assembly of claim 1, wherein the shaft engaging portion of the detent includes at least one flat surface.

12. The adjustable length punch assembly of claim 1, wherein the catch is movable between a first position in which the engaging portion of the catch engages the lock shaft and a second position in which the engaging portion of the catch is disengaged from the lock shaft.

13. The adjustable length punch assembly of claim 1, wherein the lock shaft includes at least one tooth.

14. The adjustable length punch assembly of claim 1, wherein the lock shaft includes at least one flat surface.

15. The adjustable length punch assembly of claim 1,

the lock shaft includes a plurality of teeth; and

the shaft engaging portion of the latch opening facing the longitudinal axis includes a toothed surface movable into and out of engagement with the latch shaft in response to movement of the latch along the latch channel.