US2811137A - Actuator lock mechanism - Google Patents

Description

Oct. 29, 1957 E. H. HARTEL 2,811,137

ACTUATOR LOCK MECHANISM Filed Nov. 14, 1955 IN V EN TOR.

ERWIN H. HARTEL BY l Arron/vir United States Patent 2,811,137 ACTUATOR LOCK MECHANISKM Erwin H. Hartel, Cleveland, Ohio, assignor to The Cleveland Pneumatic Tool Company, Cleveland, Ohio, a corporation of Ohio Application November 14, 1955, Serial No. 546,632 Claims. (Cl. 121-40) This invention relates to actuators in general and more particularly to a new and improved actuator lock mechanism adapted to lock the actuator in one extreme position of its stroke.

It is an important object of this invention to provide an actuator lock mechanism which is light weight and dependable in operation.

It is another important object of this invention to provide a combination actuator and lock therefor which locks the actuator in one extreme position of its stroke and which is released by the pressure fluid used to operate the actuator.

It is still another object of this invention to provide an actuator including relatively movable piston and cylinder members wherein a lock plunger is mounted in the piston member for axial movement relative thereto in suchl a manner that the piston member is releasably locked in one extreme position of its stroke.

Further objects and advantages will appear from the following description and drawings, wherein:

Figure 1 is a side elevation of an actuator incorporating a lock mechanism according to this invention;

Figure 2 is a side elevation in longitudinal section showing the actuator and lock structure with the elements in the locked position;

Figure 3 is a view similar to Figure 2 showing the position of the elements in the unlocked position; and,

Figure 4 is a fragmentary perspective View of the latch portion of the lock mechanism.

Referring to the drawings, an actuator incorporating a lock mechanism according to this invention is provided with a cylinder pivotally connected at one end as at 9 to a base or frame 11 and provided with a piston tube 12 extending from the other end. The piston tube 12 is pivotally connected to a load arm 13 by a trunnion member 14 in such a manner that axial movement of the piston tube rotates the load arm around a pivot 16 on the frame or base 11. The load arm 13 is provided with a pivot bore 18 to which a load can be connected. The various elements are shown in solid in Figure 1 with the piston tube 12 in the left hand extreme position of its stroke, and in phantom with the piston tube in the right hand extreme position of its stroke. When the piston tube 12 moves between the two extreme positions, the load arm 13 rotates around the pivot 16 through an angle A.

Referring to Figures 2 and 3, the piston tube 12 is formed with a piston head 21 which moves along a cylinder wall 19 formed in the cylinder 10. 'Ihe right or outer end of the piston tube 12 is supported by a gland member 28 which is mounted in the right end of the cylinder 10 against a shoulder 29 by a gland nut 31. Thus the piston tube V12 is axially movable within the cylinder 10 between a left hand extreme position wherein the left end of the piston tube 12 engages a radial wall 4t) formed in the cylinder 10 and a right hand extreme position wherein the piston-head 21 engages a skirt portion 55 formed on the gland member 28.

The piston tube 12 is provided with a irst axial bore 22 and a second larger coaxial bore 24 through which a lock plunger 23 projects. A piston head 26 formed 0n 2,81 1,13 7 VPatented Oct. 29, 1 957 the lock plunger 23 engages the wall of the second bore 24 to laterally support the left end of the lock plunger 23 while the right end thereof is supported by a bearing portion 27 formed in the piston tube 12. Thus the lock plunger 23 is carried by the piston tube 12 and is axially movable relative thereto between a left hand extreme position wherein the left end of the lock plunger 23 engages a radial wall 41 on a stop member 39 which is threaded into the end of the piston tube 12 and a right hand extreme position wherein the piston head 26 engages a shoulder 38 between the two bores 22 and 24. The lock plunger 23 is normally maintained in its left hand extreme position by a spring 42 which extends between a collar 43 on the lock plunger 23 and a radial wall 44 on the piston tube 12.

The gland member 28 is provided with a pair of seals 32 which prevent fluid leakage out of the cylinder 10 and the piston heads 21 and 26 are provided with uid seals 32a which prevent leakage of fluid past the piston heads.v divided into two chambers 33 and 34 which are adapted to receive pressure fluid. It should be understood that the chamber 33 includes the zone around the piston tube to the left of the piston head 21 as well as the zone within the bore 24 to the left of the piston head 26. VFluid communication is provided between these two zones through radial ports 36. Therefore pressure fluid in the chamber 33 produces an axial force to the right on the piston head 26 as well as on the piston head 21. However, pressure lluid in the chamber 34 only produces an kaxial force on the piston head 21 because the piston head 26 is not exposed to pressure fluid in this chamber. Pressure lines 37 and 35 provide a fluid connection between a source of pressure (not shown) and the two chambers 33 and 34 respectively. A port 56 formed in the skirt 55 to permit uid to flow freely between the pressure line 35 and the chamber 34. A suitable valve mechanism should be provided to selectively connect one of the chambers 33 or 34 to the source of pressure uid and also connect the other chamber to a reservoir return.

The frame or base 11 is provided with a pair of stationary pins 46 which are parallel to the` axis of the actuator when it is locked. These pins are proportioned to project through cooperating bores 47 formed in a latch member 48 which is in turn mounted on the end of the lock plunger 23 by a cross pin 49. The various proportions are arranged so that the load arm 13 is inclined relative to the axis of the cylinder 10 when the piston 12 is in the left hand extreme position. In other words, the line through the center of the pivot 16 and the trunnion member 14 intersects the axis of the piston 12 to form an angle B which is substantially largerV than Therefore, when the load arm 13 rotates from the left hand extreme position, which is the locked position shown in solid in Figure 1, to the phantom position, the initial movement of the piston tube 12 is inclined relative to its axis so that there is initially a vertical or normal component of movement. The pins 46 provide surfaces parallel to the axis of said piston which are engaged by the walls of the bores 47 and prevent such vertical or normal movement so long as they project through the cooperating bores 47 formed in the latch member 48. Therefore, the load arm 13 cannot be rotated from the locked position while the lock plunger is in the left hand or locked position. It should be understood Vthat the spring 42 holds the lock plunger 23 in this position when pressure lluid is not supplied to the chamber 33. As soon as pressure fluid is supplied to' the chamber 33 through the pressure line 37, the lock' plunger 23 moves to the right against the force of the spring l42 until the vlatch member 48 moves clear of the pins 46. At this time the load armx13 can rotate in a clockwise direction'faro'und Therefore, the cavity within the cylinder 10 is the pivot 16 under the inuence of pressure lluid in the chamber 33. This movement will continue until the piston head 21 engages the stop skirt 55 formed on the gland member 28 which limits its movement to the right.

When it is desired to operate the actuator to move the load arm 13 from the phantom position of Figure l back to the locked position, pressure iiuid is introduced into the chamber 34 and the piston 12 moves to the left toward the position shown in Figure 2. The latch member 48 is provided with a lower portion 51 which engages the ends of the pin 46 as the piston approaches the locked position. This overcomes the force of the spring 42 and prevents the lock plunger 23 from moving axially with the piston 12 as the latter continues to the lett. As soon as the piston rod 12 has moved to the left extreme position, the pins 46 are aligned with the cooperating bores 47 so that the force of the spring 42 can move the lock plunger to the lett relative to the piston rod 12. The elements then assume the position shown in Figure 2 at which time the actuator is again locked. A key 57 on the piston tube 12 projects into an axial groove 58 on the lock plunger 23 and prevents relative rotation between the two members so that bores 47 will. always align with the pin 46. Those skilled in the art will recognize that an actuator and lock according to this invention has many uses wherein the connected load must be mechanically locked in one position while being movable by the actuator to other positions.

Although a preferred embodiment of this invention is illustrated, it will be realized that various modifications of the structural details may be made without departing. from the mode of operation and the essence of the invention. Therefore, except insofar as they are claimed in the appended claims, structural details may be varied. widely without modifying the mode of operation. Accordingly, the appended claims and not the aforesaid detailed description are determinative of the scope of the invention.

I claim:

l. An actuator comprising cooperating piston and cylinder members axially movable relative to each other in response to pressure uid, a load on a base with one portion constrained to move in a predetermined locus, one of said members being connected to said base and the other to said one portion of said load, lock meansI carried by said other member axially movable relative thereto between a locked position and an unlocked position and movable from said locked position to said unlocked position in response to said pressure uid, spring means biasing` said lock means toward said locked position, and a latch engageable by said lock means only when said lock means are in said locked position, said predetermined locus being inclined relative to the axis of said members when said latch and lock means are engaged, said latch and lock means preventing movement of said lock means and other member along said predetermined locus upon said engagement.

2. An actuator comprising cooperating piston and cylinder members axially movable relative to each other in response to pressureI uid, a loadon a base with one portion constrained to move in a predetermined locus,- one of said members being connected to said base and the other to said one portion of said load, lock means carried by said other member axially movable relative thereto between a locked position and an unlocked posi-y tion and movable from said locked position to said unlocked position in response to said pressure fluid, spring 3. An actuator comprising a cylinder member, a piston member in said cylinder member cooperating therewith to dene a chamber adapted to receive pressure fluid and thereby produce relative axial motion between said members from a iirst to a second relative position, a load on a base with one portion constrained to move in a predetermined locus, one of said members being connected to said base and the other to said one position of said load, lock means carried by said other member axially movable relative thereto from a locked position to an unlocked position in response to pressure uid in said chamber, spring means biasing said lock means toward said locked position, and a latch on said base engageable by said lock means only when said lock means is in said locked position andk said members are in said rst position, said predetermined locus being inclined relative to the axis of said members when said latch and lock means.

are engaged, said latch and lock means being proportioned to prevent movement ot said lock means and other member along said predetermined locus upon said engagement.

4. An actuator comprising a cylinder, a piston in said cylinder cooperating therewith to define a chamber adapted to receive pressure fluid and thereby produces relative axial motion between said piston and cylinder from a irst to a second relative position, said piston being formed with an axial passage, a lock plunger exposed to said chamber axially movable in said passage between a locked and an unlocked position, spring means normally maintaining said lock plunger in said locked position, said lock plunger being movable in response to said pressure fluid to said'unlocked position, said cylinder being pivotally connected to a frame and said piston being pivotally connected to a load arm which is in turn pivoted on said frame, the proportions being arranged so that movement of said piston from said first position rotates said load arm around its pivot on said frame and moves the pivot of said piston on said load `arm in a direction inclined relative to the axis of said piston, latch means operably connected between said lock plunger and frame providing a surface parallel to the axis of said piston adapted to vprevent movement of said lock. plunger and in turn said piston in said inclined4 direction only when said piston is in said first position and said lock plunger is in said locked position.

5. An actuator comprising a cylinder, a piston in said cylinder cooperating therewith to define a chamber adapted to receive pressure iiuid and thereby produces relative axial motion between said piston and cylinder from. a rst to a second relative position, said piston being' formed with an axial. passage, a lock plunger exposed to said chamber axially movable in said passage between a locked and an unlocked position, spring means normally maintaining said lock plunger in said locked position, said lock plunger being movable' in response to said pressure fluid to said unlocked position, said cylinder being pivotally connected to a frame and said piston being pivotally connected tol a load arm which is in turn pivoted on said frame, the proportions being arranged so that movement of said piston from said first position rotates said load arm around its pivot on said frame and moves the pivot of said piston on said load arm in a direction inclined relative tol the axis of saidv piston, a latch member on said: lock plunger formed with a bore parallel to the axis means biasing said lock means toward said locked position, and a latch engageable by said lock means only whenI said Ylock meansare in said locked position, said predetermined locus being inclined relative to the axis of said members when both said latch and lock means are engaged, said latch and lock means permitting movement of saidlock means and otherv member only in a direction along the axis thereof upon said engagement.

of said piston, a stationary pin on said frame projecting into said. latch member bore only when said piston is in said iirst position and said lock plunger is in said lockedposition, said pin preventing movement of said lock plunger and in turn said piston in said inclined direction when it' projects into said latch member bore.

References cned in the sie of this parent FOREIGN PATENTS 577,947 i Great Britain June 6, 1946

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