US3487988A

US3487988A - Slide feed mechanism

Info

Publication number: US3487988A
Application number: US672368A
Authority: US
Inventors: Frederick Thurlow Goodwin
Original assignee: Baird Corp
Current assignee: US BAIRD Corp A CORP OF CT; Baird Corp; U S BAIRD CORP
Priority date: 1967-10-02
Filing date: 1967-10-02
Publication date: 1970-01-06
Anticipated expiration: 1987-01-06

Description

Wan. W 1970 F oo wg 3,487,988

SLIDE FEED MECHAN I SM 3 Sheets-Sheet 1 Filed Oct. 2, 1967 INVENTOR.

FIFEUE/P/CK THUELOW GUOUM/IIV BY M 2 ,9 TMRNEYS.

1970 F. T. sooowm' SLIDE FEED MECHANISM 3 Sheets-Sheet 2 Filed Oct.

a whu INVENTOR. FEEDER/6K Till/40141 aoaaww Jan. 6, 1970 F. T. GOODWIN SLIDE FEED MECHANISM s Sheets-Sheet a Filed Oct. 2, 1967 INVENTOR.

United States Patent O 3,487,988 SLIDE FEED MECHANISM Frederick Thur-low Goodwin, Stratford, Conn., assignor to The US. Baird Corporation, Stratford, Conn., a corporation of Connecticut Filed Oct. 2, 1967, Ser. No. 672,368 Int. Cl. B65h 17/18 US Cl. 226-163 Claims ABSTRACT OF THE DISCLOSURE A slide feed mechanism including a longitudinally reciprocable clamping block having a toggle linkage stock gripping arrangement positively actuable both to grip and to release the stock in timed sequence. The toggle linkage is actuable by means of a pair of roller followers which are driven by a timing gripper bar.

BACKGROUND OF THE INVENTION My invention relates to an improved slide feed mechanism and more particularly to such a mechanism including a clamping means providing a positive grip and release action.

Slide feed mechanisms are utilized in conjunction with continuously operating metal forming machines such as those that form wire or strip stock. Such mechanisms transport the metal stock from a supply source to a work station in the precise feed lengths required to perform the forming operations. Mechanism of this type include a suitable clamping means to grasp the metal stock adjacent the supply source, driving means to move the clamping means longitudinally from a stock pick-up station to a stock release station and timing means to actuate the clamping means to grasp the stock at the beginning of the stroke and to release the stock at the end of the stroke. It is critical that both the driving means and the timing means be synchronized with one another as well as with the metal forming machine.

Clamping means common to most prior art slide feed mechanisms include a clamping block actuate by a gripper timing cam and timing linkage which causes the block to positively grasp the stock on the feed stroke and which causes the block to release the stock by means of a return spring. In another form of prior art device the gripper linkage operates in a vertical plane and relies upon gravitational return of the linkage to release the stock at the end of the feed stroke. Mechanisms utilizing a spring return are not reliable in terms of perfect synchronous operation since the release action of the spring return gripper heads may become sluggish if, for example, the gripper plates become embedded in soft stock or if there is a buildup of foreign matter around the gripper linkage thus preventing the spring from exerting the force necessary to release the stock. Sluggishness will adversely affect the timing of slide feed and the metal forming machine and may even result in broken or damaged tools. Furthermore, the entire timing cycle may be halted by breakdown of the spring due to fatigue. Those prior art timing linkages which rely upon gravitational return are less reliable than the spring return mechanism since sluggishness is more likely to occur when there is a buildup of foreign materials upon the gripper linkage.

Improper synchronization between the timing means and the driving means is especially prevalent when slide feed mechanisms of the above type are used in conjunction with usual multiple slide machines. These machines inelude peripheral drive shafts connected by bevel gears. When known slide feed mechanisms are used therewith the timing means and the driving means are usually connected to adjacent shafts across one of the corners of the ice usual machine bed. The backlash in the bevel gears often causes the timing means and driving means to be out of phase.

SUMMARY OF THE INVENTION Therefore, it is the primary object of my invention to provide a slide feed mechanism having a timing linkage for driving the gripper plates both with a positive grip and release action and which will afford synchronous operation to insure feeding of accurate stock lengths.

Another object is to provide a slide feed mechanism with a quick acting, simple and unique adjusting means for clamping various stock thicknesses and having additional means to automatically compensate for variations in a given stock thickness.

Still another object is to provide a slide feed mechanism in which the timing means and the driving means are always properly synchronized.

To accomplish the primary object, in one form, I have provided a slide feed mechanism for feeding stock to metal forming machines comprising: a support; an elongated slide bar mounted upon the support; a clamping block mounted on the slide bar for longitudinal reciprocation thereon; drive means for moving the clamping block in a stock feeding direction and in a retracting direction; gripping means mounted upon the clamping block to grip and release the stock; and timing means for operating the gripping means in proper timed sequence with the driving means both to positively move the gripping means to grip the stock while the clamping block is moved in the feeding direction and to release the stock while the clamping block is moved in the retracting direction.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and further details of that which I believe to be novel and my invention will be clear from the following description and claims taken with the accompanyin g drawings, wherein:

FIG. 1 is a top plan view of the slide feed mechanism of my invention shown mounted upon and driven by a metal forming machine;

FIG. 2 is a section taken substantially along line 2-2 of FIG. 1 showing a portion of the slidable clamping block and the gripper timing means;

FIG. 3 is a section taken substantially along line 3--3 of FIG. 1 showing the gripper timing means;

FIG. 4 is a section taken substantially along line 44 of FIG. 1 showing the clamping block driving means;

FIG. 5 is a front elevational view of my unique clamping block partially broken away to show the eccentric shaft mounting;

FIG. 6 is a side elevational view of my unique clamping block;

FIG. 7 is a section taken substantially along line 77 of FIG. 5 showing the gripper timing toggle linkage;

FIG. 8 is a section taken substantially along line 88 of FIG. 5 showing the throw-out mechanism for selectively rendering the gripper plates inoperative; and

FIG. 9 is a section taken substantially along line 9-'9 of FIG. 4 showing the right hand adjustable stop member.

DESCRIPTION OF THE PREFERRED EMBODIMENT With particular reference to FIGS. 14 there is illustrated a slide feed mechanism indicated generally by the numeral 10 being mounted upon the bed 12 and driven by the left hand drive shaft 14 of a usual multiple slide metal forming machine. Of course, it should be understood that my novel slide feed mechanism may be mounted upon and driven by various types of metal forming machines or if desired may incorporate its own driving means and may be used in conjunction with various types of machines. Spaced from the bed 12 I have pro vided a slide feed supporting platform 16 upon which is mounted a bracket 18 to which one end of slide bar 20 is firmly secured, the other end being secured by suitable securing screws to a bracket 22 mounted upon the bed 12. A reciprocable clamping block 24 rides along the slide bar 20 being driven therealong by a drive assembly 26 and includes means to grip and release the stock S in a properly timed sequence by means of a timing assembly 28 having a gripper linkage subassembly 30. Both the drive assembly 26 and the timing assembly 28 are driven by the left hand drive shaft 14 as will be described hereinafter, thus insuring proper synchronization by eliminating the backlash problem prevalent in the prior art mechanisms.

A single spur gear 32 is mounted upon the left hand drive shaft 14 and includes a cylindrical boss 34 extending from one face thereof upon which is mounted a boxtype timing cam 36. The timing cam is adjustably secured to the spur gear 32 by means of a plurality of circumferentially disposed screws 38 which are threadedly anchored in tapped holes formed in the spur gear and pass through arcuate slots formed in the timing cam. In this manner, the gripper timing may be accurately controlled.'The interaction of the timing box cam 36 with the clamping block will be more fully described hereinafter. The spur gear 32 meshes with a mating spur gear 40 mounted upon a shaft 42 suitably supported by

brackets

44 and 46. The shaft 42 may be formed integrally with an eccentric drive cam 48 as shown but may, of course, be formed separate therefrom and secured thereto in a known manner. The drive assembly 26 further includes a pitman 50 adjustably secured to the eccentric cam 48 upon a diametral adjusting screw 52 which allows one end of the pitman 50 to be adjustably radially positioned upon the eccentric cam 48 to vary its stroke. The other end of the pitman may be secured to a feed drive lever 54 in one of several positions to provide further feed stroke adjustability. The feed drive lever is pivotally secured to a fixed support 56 at its lower end 58 and to a driving link 60 at its upper end 62. The driving link 60 is connected by means of a usual adjusting screw 66 to a clevis 68 which is secured to a lug 70 formed on the clamping block 24.

The reciprocable clamping block 24 straddles the slide bar 20 and is longitudinally propelled therealong by means of the drive assembly 26 just described. It should be noted that adequate means have been provided for varying the stroke of the clamping block including the diametral adjusting screw 52 and the plural adjustable pivot points throughout the linkage. The slide bar is formed with a dovetail cross'section having upper and lower bevelled

bearing surfaces

72 and 74 and further includes a longitudinal opening 76 defined therethrough, the upper and lower walls defining the opening being formed with upper and lower

central ribs

78 and 80. The

ribs

78 and 80 form supports for adjustable left hand and right hand stop

members

82 and 84 which may be clamped thereupon -(note FIG. 9), each comprising a T- shaped portion 86, a plate portion 88, a plurality of securing screws and a stop screw 92. The

stop members

82 and 84 cooperate with left hand and right

hand stop pins

94 and 96 mounted upon the clamping block 24 to positively limit the stroke of the clamping block.

The clamping block 24 shown in detail in FIGS. 57 comprises a front portion 98 and a rear portion 100 secured together by a plurality of securing screws 102. The front and rear portions are assembled to straddle the dovetail slide bar 20 and slide thereupon on upper and lower bevelled bearing blocks 104 and 106 secured to the front portion 98 by means of securing screws 108. The rear portion 100 comprises a frame having a spaced remote wall 110 which is connected to the frame by upper and lower thin wall sections 112 and defines an opening 114 through which the stock S may pass to be gripped by a suitable timed gripper arrangement actuable within the clamping block 24. Upon the left hand or stock entering side of the clamping block 24, as viewed in FIG. 5, I have provided upper and lower stock guides 116 and 118 which are vertically adjustably mounted upon the rear portion 100 adjacent the opening 114 to support the stock and guide it to the timed gripper arrangement. The stock guides include hardened support shoes 120 preferably formed of a carbide or other suitable material able to withstand the friction of the continuously passing stock S. i

The gripper arrangement comprises a backing plate 122 mounted upon the spaced remote wall 110 which cooperates with a movable gripping die 124 to which is secured a gripping plate 126 for gripping the stock S in response to the clamping movement of the gripper linkage subassembly 30. The force transmitting gripper linkage is preferably in the form of a toggle linkage which will exert a great force upon the

plates

122 and 126 for positively grasping the stock S. The thin wall sections 112 allow the spaced remote wall 110 to give under the influence of the gripping force thereby preventing fracture of the remote wall under this heavy load. To aid in gripping the stock S I have also provided the faces of the backing plate 122 and the gripping plate 126 with a plurality of vertica relieving grooves (no-t shown) to afford a better grip by these plates upon the stock which may have grease or oil on its surface.

The gripper toggle linkage comprises a connecting link 130 pivotally secured at one end to the gripping die by means of a pivot pin 132 and pivotally secured at its other end to a control lever 134 by means of a pivot pin 136. The control lever 134 is supported for rotation upon the central cylindrical portion 138 of an eccentric shaft 140. The eccentric shaft includes smaller diameter axially extending radially offset support portions 142 which are mounted for rotation in support plates 144 secured to the front portion 98 of the clamping block 24. The left end of the eccentric shaft 140, as viewed in FIG. 5, includes an adjusting portion which extends axially beyond the end of clamping block and comprises a smaller diameter cylindrical portion 146, coaxial with the central portion 138, and a non-circular key end 148, shown as being hexagonal, which may be grasped by a suitable tool to selectively adjust the angular position of the eccentric shaft 140. As the eccentric shaft 140 is rotated the radially offset support portions 142 rotate within the fixed support plates 144 causing the central portion 138 to move the control lever 134 transversely with respect to the clamping block. In this manner it is possible to adjust the toggle linkage 128 for variation in stock thickness. A U-shaped clamp also mounted upon the left side of the clamping block receives the cylindrical portion 146 and includes a tightening screw 152 which may be tightened to urge the legs of the clamp together to lock the eccentric shaft 140 in position. Once the proper angular position of the eccentric shaft is set it may be located in place by tightening the U-shaped clamp 150.

The control lever 134 includes upper and

lower control arms

154 and 156 upon which are supported upper and

lower roller followers

158 and 160 respectively. The lower roller follower 160 is rotatably mounted upon a roller pin 162 having an enlarged roller retaining head 164 and being secured in an aperture 166 formed in the lower arm 156 by a set screw 168. The upper roller follower 158 is rotatably mounted upon a roller pin 170 (note FIG. 8) having an enlarged roller retaining head 172 and being secured in an aperture 174 eccentrically defined in the cylindrical body portion 175 of a roller follower throw-out lever 176. The body portion 175 is in turn rotatably mounted in an aperture 178 defined in the upper control arm 154. The throw-out lever 176 includes a radially offset axially extending tubular arm 180 within which is disposed a spring biased locking pin 182 carrying a throw-out handle 184 to which is secured a cross-mounted gripping dowel pin 186. A compression spring 188 urges the locking pin 182 into a first locking aperture 190 formed in the upper control arm 154. A second locking aperture 192 is formed in the upper control arm diametrally opposing the first aperture 190.

When the locking pin 182 is located in the first aperture 190 the upper roller follower 158- is an operative element of the timing assembly 28, however, when the throw-out lever has been swung 180 to allow the locking pin to enter the second aperture 192 the upper roller follower is in an inoperative position (note dot-dash lines in FIG. 5).

The timing assembly 28 as illustrated in FIGS. 2, 3 and 5-7 includes the timing box cam 36 which is secured to the drive spur gear 32. A box cam roller follower 194 rides in cam track 196 and is rotatably mounted upon a follower arm 198 firmly secured to the mid-point of a drive link 200. Drive link 200 is pivotally secured at one end to the bracket 46 and at its other end is pivotally secured to the timing gripper bar 202 which extends from the bracket 46 to the support platform 16. The end of the gripper bar 202 adjacent the support platform is pinned to one end of a pivot link arm 204 the other end of which is pivotally secured to a bracket 206 firmly mounted upon the support platform 16. The gripper bar 202, the drive link 200 and the pivot link 204 form a parallelogram movement allowing the gripper bar 202 to remain horizontal as the

links

200 and 204 oscillate. The vertical component of the gripper bar motion is transmitted to the upper and

lower roller followers

158 and 160 to actuate the gripper linkage subassembly 30 as the clamping block 24 reciprocates upon the slide bar 20. The timing box cam 36 is formed to cause the gripper bar to remain in its upper position for substantially the entire length of forward travel of the clamping block 24 and to remain in its lower position for the rearward travel of the clamping block. When the gripper bar 202 is in its upper position the control level 134 is rotated counterclockwise, as viewed in FIG. 7, to urge the gripping plate 126 towards the backing plate 122 to grip the stock S. When the gripper bar is in its lower position it positively urges the lower roller follower 160 downward to rotate the control lever 134 in a clockwise direction to cause the gripper linkage 30 to release the stock. If it is desired to render the gripping action inoperative it is merely necessary to grasp the gripping dowel pin 186 and to rotate the throw-out lever 176 180 to move the eccentrically mounted upper roller follower 158 to an upper position in which it can no longer be contacted by the gripper bar 202.

Having described my invention of a feed drive mechanism it will be appreciated by those skilled in this art that a. feed drive mechanism embodying my invention is both simple in design and ingenious in operation. I have provided a novel stock gripping apparatus incorporating a powerful toggle linkage which is positively operable by means of two

roller followers

158 and 160 to insure both positive gripping and release of the stock S and thereby to insure feeding of accurate feed lengths. Further, it should be noted that I have incorporated a quick acting foolproof device for rendering the gripping action inoperative. I have also provided unique easily adjustable means to control the separation between the stock gripping plates for various stock thicknesses comprising an eccentric shaft upon which the toggle linkage control lever 134 is mounted. Furthermore, I have designed a clamping block which includes a slightly resilient spaced remote rear wall 110 upon which the backing plate 122 is mounted thus compensating for slight variations in a given stock thickness. Reliability of operation was of primary concern although ease of assembly and minimum cost of manufacture were also important conside-rations leading to the invention of my unique mechanism.

It should be understood that the present disclosure has been made only by way of example and that numerous changes in details of construction and the combination and arrangement of parts may be resorted to without departing from the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A slide feed mechanism for feeding stock to metal forming machines comprising: a support; an elongated slide bar mounted upon said support; a clamping block mounted for longitudinal reciprocation upon said slide bar and movable in a stock feeding direction and in a retracting direction; drive means for moving said clamping block upon said slide bar; gripping means carried by said clamping block to grip and release stock and being operable in a direction transverse to the direction of clamping block movement; and timing means for operating said gripping means in proper timed sequence with said driving means, said timing means including a control lever mounted upon said clamping block and secured to said gripping means and elongated camming means disposed substantially parallel to and being positively driven to reciprocate in a direction transverse to the direction of said clamping block movement, said elongated camming means engaging said control lever to move said lever positively in a first direction to cause said gripping means to grip the stock while said clamping block is moved in the feeding direction and to move said lever positively in a second direction to cause said gripping means to release the stock while said clamping block is moved in the retracting direction.

2. The slide feed mechanism defined in claim 1 wherein said timing means further includes a toggle linkage arrangement connecting said gripping means and said control lever.

3. The slide feed mechanism defined in claim 2 wherein said gripping means is positioned on one side of said slide bar and said camming means is positioned on another side of said slide bar and said slide bar includes an elongated opening defined substantially through its entire length and wherein said toggle linkage arrangement passes through said opening to operate said gripping means.

4. The slide feed mechanism defined in claim 3 further including a shaft supported on said clamping block and wherein said control lever is pivotally mounted upon said shaft and further includes a first cam follower positioned thereupon on one side of said shaft and a second cam follower positioned thereupon on another side of said shaft, said cam followers straddling said elongated camming means to rotate said lever about said shaft in respouse to the reciprocation of said camming means to operate said toggle linkage and wherein said control lever further includes a throw-out lever mounted for rotation thereon and upon which said first cam follower is eccentrically mounted to allow said first cam follower to be selectively moved from a first position in which it contacts said camming means to a second position in which it cannot contact said camming means, thus rendering said gripping means inoperative.

5. The slide feed mechanism defined in claim 3 including: a shaft supported on said clamping block and wherein said control lever is pivotally mounted upon said shaft and further includes a first cam follower positioned thereupon on one side of said shaft and a second cam follower positioned thereupon on another side of said shaft, said cam followers straddling said elongated camming means to rotate said lever about said shaft in response to the reciprocation of said camming means to operate said toggle linkage; said shaft includes a control lever support portion, eccentric bearing portions which support said shaft in said clamping block, a key portion for allowing said shaft to be selectively rotated, and a locking portion for allowing said shaft to be secured in a given angular position; and said clamping block further includes means for receiving said locking portion and for securing said shaft in a selectively predetermined position, whereby when said shaft is selectively rotated said bearing portions turn in said clamping block to move said control lever support portion laterally toward or away from said gripping means for adjusting said grippingmeans for various thicknesses of stock.

6. The slide feed mechanism defined in claim 1 further including a shaft supported on said clamping block and wherein said control lever is pivotally mounted upon said shaft and further includes a first cam follower positioned thereupon on one side of said shaft and a second cam follower positioned thereupon on another side of said shaft, said cam followers straddling said elongated camming means to rotate said control lever about said shaft in response to the reciprocation of said camming means to operate said toggle linkage.

7. The slide feed mechanism defined in claim 6 wherein said control lever further includes a throw-out lever mounted for rotation thereon and upon which said first cam follower is eccentrically mounted to allow said first cam follower to be selectively moved from a first position in which it contacts said camming means to a second position in which it cannot contact said camming means, thus rendering said gripping means inoperative.

8. The slide feed mechanism defined in claim 6 wherein; said shaft includes a control lever support portion, eccentric bearing portions which support said shaft in said clamping block, a key portion for allowing said shaft to be selectively rotated and a locking portion for allowing said shaft to be secured in a given angular position; and said clamping block further includes means for receiving said locking portion and for securing said shaft in a selectively predetermined position, whereby when said shaft is selectively rotated said bearing portions turn in said clamping block to move said control lever support portion laterally toward or away from said gripping means for adjusting said gripping means for various thicknesses of stock.

9. The slide feed mechanism defined in claim 1 wherein: said clamping block includes a body portion a rear wall spaced from said body portion and secured thereto by thin wall portions defining a longitudinal opening in said clamping block through which the stock may pass; and said gripping means includes a reciprocable gripping plate moved by said timing means and a backing plate secured to said rear wall.

10. The slide feed mechanism defined in claim 1 wherein said timing means includes a box cam, a cam follower, a follower arm to which said cam follower is secured, and a parallelogram linkage driven by said follower arm, and said elongated camming means comprises the central link of said parallelogram linkage.

References Cited UNITED STATES PATENTS 2,798,234 7/1957 Benninghofi 226163 X 2,884,119 4/1959 Powers 226l63 3,161,338 12/1964 Grimm 226-163 M. HENSON WOOD, JR., Primary Examiner R. A. SCHACHER, Assistant Examiner