US3862564A

US3862564A - Machine press with positive cam driven sliding bed and cam activated auxiliary systems

Info

Publication number: US3862564A
Application number: US417579A
Authority: US
Inventors: Robert Blase
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-10-26
Filing date: 1973-11-20
Publication date: 1975-01-28
Anticipated expiration: 1992-01-28

Abstract

A machine press is disclosed having a base and vertical supports upstanding therefrom, a motor-driven crankshaft rotatably mounted in the vertical supports, and a ram mounted for vertical sliding movement driven by a connecting rod interconnecting the crankshaft and the ram. A bed is mounted for horizontal sliding movement under the ram, and is driven by a cam engaging two cam followers upstanding from the bed. The cam is connected to a shaft which is driven from the crankshaft through two-to-one reduction bevel gears. The cam is symmetrical, and provides two zero velocity positions of the bed coordinated with the lowermost position of the ram. Die sets comprising a plurality of steppedheight dies arrayed parallel to the motion of the sliding bed are mounted in the machine press; the lower half of the die set being mounted on the sliding bed, and the upper half being mounted on the ram. The dies come together for a stamping operation when the bed is at a first zero velocity position, and the dies are indexed one die for transfer operations when the bed is at its second zero velocity position. Additional cams are mounted on the second shaft, and these cams operate sensors controlling auxiliary devices, such as parts ejectors and missing parts detectors.

Description

United States Patent Blase MACHINE PRESS WITH POSITIVE CAM DRIVEN SLIDING BED AND CAM ACTIVATED AUXILIARY SYSTEMS Primary ExaminerC. W. Lanham Assistant ExaminerGene P. Crosby Attorney, Agent, or Firm-Mattern, Ware & Davis [57] ABSTRACT A machine press is disclosed having a base and vertical supports upstanding therefrom, a motor-driven crankshaft rotatably mounted in the vertical supports, and a ram mounted for vertical sliding movement driven by a connecting rod interconnecting the crankshaft and the ram. A bed is mounted for horizontal sliding movement under the ram, and is driven by a cam engaging two cam followers upstanding from the bed. The cam is connected to a shaft which is driven from the crankshaft through two-to-one reduction bevel gears. The cam is symmetrical, and provides two zero velocity positions of the bed coordinated with the lowermost position of the ram. Die sets comprising a plurality of stepped-height dies arrayed parallel to the motion of the sliding bed are mounted in the machine press; the lower half of the die set being mounted on the sliding bed, and the upper half being mounted on the ram. The dies come together for a stamping operation when the bed is at a first zero velocity position, and the dies are indexed one die for transfer operations when the bed is at its second zero velocity position. Additional cams are mounted on the second shaft, and these cams operate sensors controlling auxiliary devices, such as parts ejectors and missing parts detectors.

14 Claims, 9 Drawing Figures [76] Inventor: Robert Blase, 1009 Round Hill Rd.,

F i LCQa -WBQ [22] Filed: Nov. 20, 1973 [21] Appl. No.: 417,579

Related U.S. Application Data [63] Continuation-impart of Ser. No. 301,165, Oct. 26,

1972, abandoned.

[52] i U.S. Cl 72/405, 72/4, 72/421 [51] Int. Cl B2lj 13/08 [58] Field of Search 72/405, 421, 448, 452, 72/4, 26; 10/125, 12 T, 76 T; 198/218 [56] References Cited UNlTED STATES PATENTS 1,426,039 8/1922 Candee 198/218 2,663,275 12/1953 Collins 72/4 2,886,886 5/1959 Hartung 72/421 3,031,698 5/1962 Friedman l0/l2.5

3,247,533 4/1966 Phipard l0/l2.5 3,319,087 5/1967 Wintriss.... 72/26 3,369,387 2/1968 Bradlee..... 72/426 3,527,073 9/1970 Wintriss.... 72/4 3,541,834 11/1970 Wallis 72/405 3,555,861 l/l971 Staecker 72/4 3,555,865 1/1971 Sebastian 72/448 PATENTEDJANZBIQTE 3,862,564

SHEET 10F 2

PATENTEU sum

2 or 2 FIG. 6

FIG. 5

MACHINE PRESS WITH POSITIVE CAM DRIVEN SLIDING BED AND CAM ACTIVATED AUXILIARY SYSTEMS CROSS-REFERENCE This application is a continuation-in-part application of Robert Blases patent application relating to Machine Press with Positive Cam Driven Sliding Bed and Cam Activated Auxiliary Systems filed Oct. 26, 1972 and bearing Ser. No. 301,165, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to machine presses, and particularly to machine presses with sliding beds for performing transfer operations. The invention further relates to machine presses having sliding beds positively driven by cams wherein the sliding beds are accurately positioned and wherein ejectors, missing parts detectors, and the like are also positively actuated by cams.

2. Prior Art Machine presses having a bed slidable under a vertically driven press member are known in the prior art. However, the prior art presses have employed various compressed air or pneumatic means for driving the bed. Typically, mechanical stops determine the position of the bed, and complicated series of relays controlling the supply of compressed air were used to drive the bed. Similarly, accessories such as ejectors were also electric-air driven, being operated by compressed air passed through a series of air relays which were in turn controlled by mechanical sensors for sensing the position of the bed and ram.

These devices were unsatisfactory in many respects. First, the positioning of the sliding bed was not precise. Also, most of the presses having beds driven by compressed air exhibited a high amount of vibration. The vibration contributed to inaccuracy and also shortened the life of the dies and the slide mechanism on which the bed was mounted.

In addition, the relays required to drive a sliding bed were extremely complicated, and required frequent repair. The repairs themselves were expensive, and also resulted in considerable down time and consequent loss of production.

SUMMARY OF THE INVENTION OBJECTS It is an object of this invention to provide improved machine presses having sliding beds.

It is a second object of this invention to provide machine presses having reliably and efficiently driven auxiliary devices.

It is an additional object of the invention to provide machine presses of the type having sliding beds wherein the sliding beds are accurately positioned for press operation.

It is an additional object of the invention to provide machine presses suitable for producing precision parts.

It is a further object of the invention to provide machine presses which are highly reliable and durable.

GENERAL DESCRIPTION tached to an overhead motorized crankshaft. A bed is mounted for sliding horizontal motion below the ram, and the second portion of the die set is carried on the sliding bed.

The sliding bed is connected to and driven from the crankshaft by a positive mechanical link comprising a shaft driven by the crankshaft through 2:1 gearing, a cam connected to the shaft and positioned adjacent to the sliding bed, and cam followers attached to the sliding bed and engaging the cam. The cam used to drive the bed provides a modified sinusoidal variation of velocity and acceleration wherein the bed is stationary at the time of contact between the two die sets and when the die sets are in close aligned proximity for transfer operations.

Additional cams are mounted on the crankshaft and shaft, and are used to actuate auxiliary devices including parts ejectors, bed position monitors, missing parts detectors, operator safety restraints or operator position sensors, or the like.

Other and more specific objects will be apparent from the features, elements, combinations and operating procedures disclosed in the following description of the preferred embodiment and shown in the drawings.

THE DRAWINGS FIG. 1 is a front view of a machine press according to the invention with its die set aligned for a transfer operation;

FIG. 2 is a sectional view of the cam, sliding bed, and relative positions of the dies of the machine press taken along the lines 2--2 of FIG. 1;

FIG. 3 is a front view partially cut away of the machine press of FIG. 1 with its die sets aligned for form- FIG. 4 is a sectional view of the cam, sliding bed, and relative positions of the dies of the machine press taken along the lines 44 of FIG. 3;

FIG. 5 is a vertical sectional view of the sliding bed and its base, taken along the lines 55 of FIG. 2;

FIG. 6 is an enlarged sectional view of a parts ejector mechanism encircled in FIG. 3;

FIG. 7 is a schematic electrical diagram of a bed position monitor of the machine press of FIG. 1;

FIG. 8 is a framentary schematic diagram of a missing parts detector of the present invention; and

FIG. 9 is a similar fragmentary schematic diagram of a modified version of the missing parts detector of FIG. 8.

The same reference numbers refer to the same elements throughout the drawings.

PREFERRED EMBODIMENT Referring now to FIG. 1, there is shown a machine press 10 according to the invention. The press comprises a base 11 having a sliding bed assembly 12 mounted thereon. The sliding bed assembly comprises a first portion 13 secured to the base 11 and having a V-shaped spline 14 comprising the male portion of a dovetail upstanding therefrom. A sliding bed 15 is mounted for linear sliding motion on plate 13, the sliding bed 15 having a groove 16 comprising the female portion of the dovetail. As best seen in FIG. 5, the V- shaped spline 14 and the groove 16 cooperate to hold the sliding bed 15 onto the base and to permit linear motion thereof. Bearings may be provided at the interface of the groove 16 and the spline 14.

The machine press further comprises two supports and 21 upstanding from the base 11, and a top plate 22 connecting the two vertical supports. Mounted on the top plate 22 is an electric motor or variable speed drive means 23 having an output shaft 24 and associated pulley 25. A drive belt 26 is engaged by the pulley and by a combination brake, clutch, and fly wheel 27 which is mounted onto a shaft 30 supported in bearings in the two

vertical supports

20 and 21. The shaft 30 has an offset portion 31, wherein the shaft 30 operates as a crankshaft.

The machine press 10 further comprises a ram 32 'slidingly mounted for vertical movement on

vertical guides

33 and 34. A connecting rod 35 is connected to the ram 32 at one end and is connected to the offset portion 31 of the shaft 30 at its other end, wherein the ram 32 makes one complete up-and-down stroke for each rotation of the shaft 30.

A first bevel gear 36 is mounted on the free end of shaft 30 adjacent to vertical support 20. The bevel gear 36 cooperates with a second bevel gear 37 to rotate a vertical shaft 40 connected to bevel gear 37. The vertical shaft 40 is supported by two

bearings

41 and 42 which are in turn supported on the vertical support 20. A third bearing (not shown) suports the lower end of shaft 40. The shaft 40 is connected to and rotates a cam 43. The cam 43 is positioned adjacent to the sliding bed 15, and upstanding from the sliding bed 15 are two

cam followers

44 and 45, wherein the sliding bed 15 is driven and accurately positioned by the cam 43, and wherein a positive mechanical link between the sliding bed 15 and the vertical sliding ram 32 is provided.

The bevel gears 36 and 37 have a 2:1 ratio, i.e. the shaft 40 is driven at V2 the speed of the speed of the shaft 30. The shape of cam 43, best seen in FIGS. 2 and 4, causes the sliding bed 15 to be driven through one in-and-out cycle for each rotation of shaft 40. The surface of cam 43 has a zero speed portion 46 wherein the surface of the cam is at a constant radius from the shaft 40. Referring now to FIG. 2, the zero speed protion 46 causes the sliding bed to be at rest with respect to the base at the outermost position of travel of the bed. The zero speed position of bed 15 is coordinated with the motion of ram 32 so that the lowermost portion of travel of ram 32 occurs when the bed 15 is motionless.

Referring now to FIGS. 3 and 4, a second zero speed position of bed 15 occurs at the innermost position achieved by bed 15. Again, the lowermost portion of vertical travel of the second downward cycle of ram 32 occurs while the bed is motionless.

A die set 50 is mounted in the machine press 10 for forming or stamping parts. The die set 50 comprises a lower plate 51 secured to the sliding bed 15. Upstanding from the lower plate 51 are four individual dies 52-55 having progressively less vertical height. A second set of cooperating dies 62-65 are mounted on a plate 56 secured to the ram 32. The dies 62-65 have progressively increasing vertical height, increment of increase being the same as the increment of decrease in height of dies 52-55. Die sets with any number of dies can be used, and four dies are shown for convenience. The lower dies 52-55 and the upper dies 62-65 are precisely aligned for performing stamping operations when the bed 15 is in its innermost position and the ram 32 is at its lowermost position, as shown in FIGS. 3 and 4. To better insure the precise alignment of the dies during both stamping and transfer operations, upstanding auxiliary guides such as guide 66, are provided on the lower die set plate 51, and mating receptacles such as receptacle 67, are provided on the upper plate 56.

Subsequent to stamping or forming operations, the parts are carried on the upper dies 62-65 for one upand-down cycle of the ram 32, during which time the bed 15 is driven to its outermost position shown in FIGS. 1 and 2. The die 62 is then aligned with die 53, and the like, and upper die 65 is positioned over a collection container 70. The upper and lower dies do not touch because of the incremented vertical heights thereof. When the dies are aligned and the ram 32 is at its lowermost position, parts ejectors forming a portion of the upper die set operate to deposit the parts carried on the die set onto the lower dies, e.g. the part formed between upper die 62 and lower die 52 is deposited onto lower die 53, whereby a further forming or stamping operation will be performed on the part between upper die 63 and lower die 53 on the next vertical cycle of the ram 32.

Referring now to FIG. 6, a typical parts ejector mechanism is shown at 71. It comprises one or more vertical rods 72 passing through the upper die 62. The vertical rods 72 butt against one end of a movable air-driven piston 73, which is provided with air through conduit 74 connected to a source of positive pressure through valve means. Synchronization of the valve opening and the motion of the sliding bed and ram are preferably coordinated by attaching an auxiliary cam 75 to shaft 40 and attaching a mechanical finger or other mechanical sensor 76 in the path of cam 75. The mechanical sensor 76 preferably directly operates an air valve wherein air is admitted through conduit 74 to move piston 73 and drive down the shafts 72 to eject the part. The sensor 76 can also operate an electric relay to accomplish the same purpose. Because of the reduced speed of shaft 40, the ejector is operated only on alternate vertical strokes of ram 32, as desired.

Other auxiliary cams can also be connected to shaft 40 for operating sensors adjacent thereto. For instance. there are shown auxiliary cams 77 and 81 (FIG. I) mounted on shaft 40 for operating sensors 80 and 82 each revolution of shaft 40. Cam 77 is positioned to trigger the sensor as the ram approaches its lowermost position, and is therefore useful in cooperation with safety devices for causing a brake to operate and stop the ram if the operators hands are not clear. The third auxiliary cam 81 attached to shaft 40 has a cooperating sensor 82 for activating a missing parts detector on each transfer stroke. The missing parts detector may be a photoelectric sensor positioned between upper die 65 and collection basket 70, and may provide an alarm signal for stopping the press if no part is produced.

Two highly useful forms of missing parts detectors are shown in FIGS. 8 and 9. In FIG. 8, the completed parts container 70 is replaced by a delivery chute 70A leading to a remote collection 708. A lateral delivery conduit 76 has its entrance juxtaposed to final upper die part 65 and its exit facing delivery chute 70A. An air jet 77 propels each completed part 78 ejected from die part 65 into and through conduit 76 and thence into chute 70A. An inductive sensor ring 79 encircles conduit 76 and is connected to a ready-or-stop control unit or stop alarm like that shown in FIG. 7.

In the alternative version of the missing parts detector shown in FIG. 9, the delivery chute 70A and lateral conduit 76 are combined in a vertically-oriented conduit 76A interposed between the overlying final die part 65 and the underlying remote collection container 708. Sensor ring 79 surrounds conduit 76A, performing the identical function described above. Air jet 77 is here replaced by the force of gravity, or by a downwardly-acting air jet 77A incorporated in upper die part 65.

In both forms of these missing parts detectors, capacitive sensors or photocell sensors may be employed if desired, in place of inductive sensor 79. Output signals from sensor 79, and cycle-in-progress signals from sensor 80 or 82 for example, are both supplied to the stop alarm unit. Omission of either signal triggers the alarm which is connected to stop the press at once for inspection.

If for any reason a part is not ejected, it may cause successive stacking of a dozen or more parts between the die sets, creating danger of tooling damage or destruction. Such damage is avoided by the missing parts detectors of this invention, since the absence of a signal from sensor ring 79 during any operating cycle stops the press instantly, to permit removal of stacked or jammed parts. Human operators assigned to monitor these automatic stamping presses may become hypnotized by watching repeated operating cycles, hour after hour, and may fail to notice stacked part jams until damage has already occurred. The missing parts detector systems of this invention sense the first missing part, making these stamping presses fully automatic for longsustained continuous operation.

Auxiliary cams can also be installed on crank shaft 30. Such cams rotate once per revolution of shaft 30, and twice per revolution of shaft 40, and therefore rotate once per vertical stroke of ram 32 and once for each complete in-out cycle of sliding bed 15.

Cam 90 is shown mounted on crank shaft 30 for operating sensor 91. Cam 90 and sensor 91 are a portion of a bed position monitoring system which further includes right and left micro-switches (shown only in FIG. 7), the right micro-switch being closed when the bed is in its far right position and the left micro-switch being closed by the bed in its far left position. The object of the monitoring system is to provide a signal for operating the brake if the sliding bed does not operate the micro-switches at the proper time, indicating some malfunction.

Referring now to FIG. 7, the right micro-switch 92 and the left micro-switch 93 are wired in parallel with the sensor 91. Cam 90 is preferably a holding cam, i.e. during a substantial portion of its rotation it holds sensor 91 closed and is timed to open sensor 91 just after either

sensor

92 or 93 is closed by the arrival of the sliding bed and is further timed to close sensor 91 just before the movement of the sliding bed opens

microswitch

92 or 93. Therefore, so long as the sliding bed reaches its proper position at the proper time, and so long as the shaft 30 is intact and rotating cam 90, a signal is provided at 94. However, if the sliding bed should fail to arrive at the proper time to close one of the

micro-switches

92 or 93, or if the shaft 30 should break or become displaced, no signal is provided at 94, thereby activating the brake mechanism and stopping further operation of the press.

Other shapes of cam 43 may be substituted to provide various types of sliding bed motion relative to the vertical ram 32. For instance, the bed may be caused to stop in three positions with an appropriate cam if the progression of the work pieces through the dies so requires. Also, additional auxiliary cams can be mounted on shaft 40 to run a variety of other auxiliary devices, such as counters, lubrications sprays, paint sprays, and the like.

The machine press described herein is sturdy and runs relatively free of vibration, wherein long life, low maintenance cost, and little down time can be expected. The machine press is adaptable to a variety of operations by substituting die sets, bed driving cams, auxiliary cams and sensing devices.

Since the foregoing description and drawings are merely illustrative, the scope of the invention has been broadly stated herein and it should be liberally interpreted to secure the benefit of all equivalents to which the invention is fairly entitled.

I claim:

1. A machine press comprising:

A. a base and supports upstanding therefrom;

B. a first motor-driven upper shaft rotatably mounted in the supports upstanding from the base;

C. a ram mounted for sliding movement perpendicular to the base;

D. connecting means for driving the ram from the first upper shaft;

E. a bed mounted for sliding movement on the base, said sliding movement being perpendicular to the movement of the ram;

F. a second shaft driven by the first shaft;

G. A first cam mounted on said second shaft adjacent to the bed;

H. cam followers upstanding from the bed and engaged by the first cam, wherein rotation of the second shaft and the first cam mounted thereon causes sliding movement of the bed.

2. A machine press as defined in claim 1 and further comprising:

1. at least one additional cam mounted on said second shaft; and

J. sensor means activated by said additional cam for controlling the operation of auxiliary devices.

3. A machine press as defined in claim 1 wherein the second shaft is driven by the first shaft through twoto-one reduction gears.

4. A machine press as defined in claim 3 wherein said first anclv second shafts are perpendicular, and wherein the reduction gears are bevel gears.

5. A machine press as defined in claim 3 wherein the first cam is symmetrical and provides a first zero velocity position of the bed when the ram is in closest proximity to the bed, and further provides a second zero velocity position of the bed when the ram is next in closest proximity to the bed.

6. A machine press as defined in claim 5 wherein the first half of a multiple-die die set is mounted on the vertical ram and the second half of the multiple-die die set is mounted on the sliding bed and wherein the dies of the first and second halves of the die set are aligned in the first zero velocity position of the bed for forming operations, and wherein some of the dies of the first and second die sets are aligned in the second zero velocity position of the bed for transfer operations.

7. A machine press as defined in claim 2 wherein one of auxiliary devices is a parts ejector.

8. A machine press as defined in claim 2 wherein one of the auxiliary devices is a missing parts detector.

9. A machine press as defined in claim 1 and further comprising:

l. at least one additional cam mounted on said first shaft; and

10. A machine press as defined in claim 9 wherein one of the auxiliary devices is a bed position sensor comprising:

a. a first micro-switch operated by the bed in a first position;

b. a second micro-switch operated by the bed in a second position;

0. means connecting the first micro-switch, the second micro-switch, and the sensor means in parallel, wherein the additional cam mounted on the first shaft is designed to change the condition of the sensor means during a portion of the period when either the first or second micro-switch is operated by the sliding bed.

11. The machine press defined in claim 8 wherein the missing parts detector comprises a completed part ejection conduit positioned to receive each completed part ejected from between die parts respectively mounted on the ram and the bed, and a proximity sensor juxtaposed to the conduit and connected to produce an output signal in response to the passage of each completed part through the conduit, and a stop alarm unit connected to receive said output signals and to stop the press operation if an output signal is not generated during each press operating cycle.

12. The machine press defined in claim 11 wherein the conduit extends laterally toward a remote collection point, and further including an air jet directed to propel each ejected part into said ejection conduit.

13. The machine press defined in claim 11 wherein said ejection conduit has an entrance portal positioned directly below the ejected parts, whereby they are delivered into said portal.

14. A machine press comprising:

A. a base and supports upstanding therefrom;

C. a ram mounted for sliding movement perpendicular to the base;

D. connecting means for driving the ram from the first upper shaft;

E. a bed mounted for sliding movement on the base, said sliding movement being perpendicular to the movement of the ram; and

F. a missing parts detector comprising a conduit through which each completed part is ejected, and a proximity sensor associated with the conduit and providing an output signal to a stop alarm unit connected to stop press operation if a completed part sensing output signal is not transmitted during any operating cycle.

Claims

1. A machine press comprising: A. a base and supports upstanding therefrom; B. a first motor-driven upper shaft rotatably mounted in the supports upstanding from the base; C. a ram mounted for sliding movement perpendicular to the base; D. connecting means for driving the ram from the first upper shaft; E. a bed mounted for sliding movement on the base, said sliding movement being perpendicular to the movement of the ram; F. a second shaft driven by the first shaft; G. A first cam mounted on said second shaft adjacent to the bed; H. cam followers upstanding from the bed and engaged by the first cam, wherein rotation of the second shaft and the first cam mounted thereon causes sliding movement of the bed.

2. A machine press as defined in claim 1 and further comprising: I. at least one additional cam mounted on said second shaft; and J. sensor means activated by said additional cam for controlling the operation of auxiliary devices.

3. A machine press as defined in claim 1 wherein the second shaft is driven by the first shaft through two-to-one reduction gears.

4. A machine press as defined in claim 3 wherein said first and second shafts are perpendicular, and wherein the reduction gears are bevel gears.

9. A machine press as defined in claim 1 and further comprising: I. at least one additional cam mounted on said first shaft; and J. sensor means activated by said additional cam for controlling the operation of auxiliary devices.

10. A machine press as defined in claim 9 wherein one of the auxiliary devices is a bed position sensor comprising: a. a first micro-switch operated by the bed in a first position; b. a second micro-switch operated by the bed in a second position; c. means connecting the first micro-switch, the second micro-switch, and the sensor means in parallel, wherein the additional cam mounted on the first shaft is designed to change the condition of the sensor means during a portion of the period when either the first or second micro-switch is operated by the sliding bed.

14. A machine press comprising: A. a base and supports upstanding therefrom; B. a first motor-driven upper shaft rotatably mounted in the supports upstanding from the base; C. a ram mounted foR sliding movement perpendicular to the base; D. connecting means for driving the ram from the first upper shaft; E. a bed mounted for sliding movement on the base, said sliding movement being perpendicular to the movement of the ram; and F. a missing parts detector comprising a conduit through which each completed part is ejected, and a proximity sensor associated with the conduit and providing an output signal to a stop alarm unit connected to stop press operation if a completed part sensing output signal is not transmitted during any operating cycle.