Linear Actuators for Chromatography

Abstract

A rod-type linear actuator for use with a housing associated with a rotatable hollow, internally threaded shaft and a piston-driven device where fine, precise movement is required is provided, the actuator including a body, a lead screw engaging the rotatable hollow, internally threaded shaft and terminating in a piston, and an anti-rotation device extending from the lead screw and engaging the body or a second, opposing body.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Application No. 63 / 393,351, filed July 29, 2022. [Background technology]

[0002] The present invention relates to a rod-type linear actuator used in conjunction with a housing and piston driven device where precise and accurate movement is required. More particularly, the present invention relates to a rod-type linear actuator used in conjunction with a motor driving a hollow threaded shaft and a piston driven device where repeatable, uniform and accurate displacement is required.

[0003] High-performance liquid chromatography (HPLC) is typically performed using pumps, injection valves, columns, and detectors, which are typically designed to deliver small volumes of sample or fluid under pressure. The flow rates delivered by pumps can be very small, requiring precise pump control and output. Such pumps are often piston-driven, requiring the piston to smoothly reciprocate at a constant forward or reverse velocity for precisely controlled displacement. To achieve this motion, the piston is connected to a linear actuator. Linear actuators used for this purpose often include a rotating element, such as a lead screw, and a corresponding nut or anti-rotation device. When a nut is used, the lead screw is fixed in place relative to the motor, resulting in the nut moving along the threads of the lead screw, thereby advancing or retracting the screw. When an anti-rotation device is used, the system operates somewhat differently. The lead screw engages with a rotatable, hollow, internally threaded shaft and an anti-rotation device, which prevents the lead screw from rotating with the lead screw and is fixed relative to the lead screw, thereby advancing or retracting the lead screw relative to the internally threaded shaft.

[0004] The problem was that if the anti-rotation device engaged the lead screw adjacent to the housing rather than near the piston, the lead screw would vibrate and fluctuate in position at the far end where the piston driven pump was located, and the piston would have to overcome the intermittent constraints involved, causing friction and wear and reducing the accuracy of the piston movement.

[0005] It is therefore desirable to provide a rod-type linear actuator for use with a housing and piston driven device associated with a rotatable hollow internally threaded shaft, the rod-type linear actuator including a body, a lead screw engaging the rotatable hollow internally threaded shaft and terminating in the piston, and an anti-rotation device extending from the lead screw and engaging either the body or an opposing second body, which reduces the possibility of piston position fluctuations and speed and position deviations. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention fulfills the above needs and overcomes one or more of the problems of the prior art. [Means for solving the problem]

[0007] To solve this problem, a rod-type actuator is disclosed that is used in combination with a housing containing an axially rotatable hollow internal threaded shaft and a motor for driving the shaft, and a piston-driven device to provide displacement. The rod-type actuator includes a body, a lead screw, an anti-rotation device, and a piston. The body has a rear surface and an opposite external front surface, and is configured to connect to the housing at the rear surface and to connect to the piston-driven device at the external front surface. The body has a first passage extending from the rear surface to the external front surface of the body about the body central axis and terminating at the internal surface of the body, the first passage having a first passage cross-sectional shape and a first passage length greater than the sum of the displacement and the anti-rotation device length. The body also has a second passage extending along the body central axis from the external front surface of the body to the internal surface of the body, the second passage length being shorter than the displacement and having a second passage cross-sectional shape narrower than the first passage cross-sectional shape. The body also has a guide pin attached to the body interior surface, extending parallel to the body central axis and having a guide pin length at least equal to the sum of the displacement and the anti-rotation device length but less than the first passage length. The lead screw has a lead screw thread portion terminating at a rear end of the lead screw and a lead screw body terminating at a first end of the lead screw opposite the rear end of the lead screw, and is configured to engage with the axially rotatable, hollow, internally threaded shaft. The lead screw thread portion has a lead screw thread length greater than the displacement. The anti-rotation device extends from the lead screw at the lead screw body, has an anti-rotation device length measuring from the front end of the anti-rotation device to the rear end of the anti-rotation device, and has a guide pin passage aligned with the guide pin. The guide pin is sized to pass through the guide pin passage, thereby allowing the anti-rotation device to slide along the guide pin. The anti-rotation device is sized to move within the first passage. A piston extends from the lead screw at the first end of the lead screw and is sized to slide reciprocate within the second passage.The piston is configured for attachment to the piston driven device and is sized to reciprocate within the second passageway with a piston length greater than the displacement.

[0008] To solve this problem, a rod-type actuator is disclosed that includes a housing containing an axially rotatable hollow internal threaded shaft and a motor for driving the shaft, and that is used with a piston-driven device to provide displacement. The rod-type actuator includes a main body, a second body, a lead screw, an anti-rotation device, and a piston. The main body has a rear surface and an opposite external front surface, and is configured to connect to the housing at the rear surface and to connect to the piston-driven device at the external front surface. The main body has a first passage extending from the rear surface to the external front surface of the main body, centered on the main axis, and terminating at the internal surface of the main body. The first passage has a first passage cross-sectional shape and a first passage length that is equal to or greater than the sum of the displacement and the anti-rotation device length. The main body also has a second passage extending along the main axis from the external front surface to the internal surface of the main body. The second passage length is shorter than the displacement and has a second passage cross-sectional shape that is narrower than the first passage cross-sectional shape. The second body is sized to be fixedly engaged with either the main body or the housing, and a guide pin is attached to the internal surface of the second body. The guide pin is parallel to the body central axis, has a guide pin cross-sectional shape, and extends toward the body inner surface a guide pin length at least equal to the sum of the displacement and the anti-rotation device length. The lead screw has a lead screw thread portion terminating at a rear end of the lead screw and a lead screw body terminating at a lead screw first end opposite the rear end of the lead screw, and is configured to engage with an axially rotatable, hollow, internally threaded shaft. The lead screw thread portion has a lead screw thread length greater than the displacement. The anti-rotation device extends from the lead screw at the lead screw body away from the body central axis, has an anti-rotation device length measuring from the front end of the anti-rotation device to the rear end of the anti-rotation device, and has a guide pin passage aligned with the guide pin. The guide pin passage has a guide pin passage cross-sectional shape that allows the anti-rotation device to slide along the guide pin. The anti-rotation device has an anti-rotation device cross-sectional shape that is sized to move within the first passage.The guide pin passage cross-sectional shape is larger than the guide pin cross-sectional shape. The piston extends from the lead screw at the first end of the lead screw and is sized to slide back and forth through the second passage. The piston has a piston length and piston cross-sectional shape sized to fit into the second passage without interfering with it.

[0009] Other features, advantages, and embodiments of the present invention will become apparent to those skilled in the art from the following description of various embodiments and the associated accompanying drawings.

[0010] The features, advantages, and objects disclosed and described above, as well as those briefly summarized above, can be understood by reading the following description in more detail with reference to the embodiments thereof as illustrated in the accompanying drawings, which form a part of this specification. It should be noted that the accompanying drawings merely illustrate typical and preferred embodiments of the present invention, and that other equally effective embodiments not shown in the drawings are also included in the present invention, and that the accompanying drawings do not limit the scope of the invention. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 shows a rod-type linear actuator in which the anti-rotation device engages a fixed guide pin extending from the body. [Figure 2] FIG. 2 shows a rod-type linear actuator where the anti-rotation device engages a fixed guide pin extending from an opposing second body. [Figure 3] FIG. 3 shows a hollow, internally threaded shaft that can rotate around its axis, attached to the end of a solid motor shaft. [Figure 4] FIG. 4 shows an axially rotatable hollow internally threaded shaft connected to a gear body. DETAILED DESCRIPTION OF THE INVENTION

[0012] Referring to FIG. 1, a rod-type linear actuator having a displacement 199 is shown in which an anti-rotation device engages a fixed guide pin extending from the body. The rod-type actuator 100 is intended for use with a housing 102 and a piston driven device 103. The housing 102 contains a motor 104, which drives a hollow, internally threaded shaft 106 disposed within the housing 102 and capable of rotating. The hollow, internally threaded shaft 106 may be located within the motor 104, at the end of a solid motor shaft 302 associated with the motor 104, or at the end 404 of a gear body 402 connected to the motor 104. The hollow, internally threaded shaft 106 located at the end of a solid motor shaft 302 associated with the motor 104 is shown in FIG. 3. The hollow, internally threaded shaft 106 located at the end 404 of a gear body 402 connected to the motor 104 is also shown in FIG. 4. The motor 104 can be a stepper motor or other motor that can be precisely controlled by an associated processor or control system, such as a computer. The piston driven device can be a pump or other device connected to the piston 136 and sealed relative to the body 108. This configuration allows precise movement of the piston 136, resulting in high operational accuracy. The rod-type actuator 100 includes the body 108, the lead screw 134, the anti-rotation device 130, and the piston 136.

[0013] The body 108 is positioned between the housing 102 and the piston driven device 103. The body 108 has a rear body surface 110 and an external front body surface 112, with the rear body surface 110 being opposite the external front body surface 112. To maintain its position, the body 108 may be configured to connect to the housing 102 at the rear surface 110 and to connect to the piston driven device 103 at the external front surface 112.

[0014] The body 108 provides an interior space through which the lead screw 134, anti-rotation device 130, and piston 136 move during operation. The body 108 has a first passageway 114 extending from the rear body surface 110 to the exterior body front surface 112 about a central body axis 116 and terminating at an interior body surface 164. The first passageway 114 may have a first passageway cross-sectional shape 118, which may be cylindrical or another first passageway cross-sectional shape, such as forming a rectangular parallelepiped. The body 108 also has a second passageway 120 extending from the exterior body front surface 112 to the interior body surface 164 along the central body axis 116. The length of the second passageway 120, defined as a second passageway length 194, is less than the displacement 199. The second passageway 120 has a second passageway cross-sectional shape 122. The first passageway cross-sectional shape 118 is complementary to the second passageway cross-sectional shape 122, and both may be cylindrical. Because second passageway 120 provides a passageway for movement of piston 136, second passageway 120 is narrower than first passageway 114. If first passageway 114 and second passageway 120 are both cylindrical, the diameter of second passageway cross-section 122 is smaller than the diameter of first passageway cross-section 118. First passageway 114 has a first passageway 114 length 193, which is greater than or equal to the sum of displacement 199 and anti-rotation device length 198.

[0015] The body 108 includes structure to prevent rotation of the anti-rotation device 130, and structure and space for advancing and retracting the lead screw 134 and piston 136. The body 108 may include a guide pin 128 secured to the body 108 at an interior body surface 164 and positioned parallel to the body central axis 116. In this configuration, the contact area of the guide pin 128 is minimized, thereby minimizing friction while ensuring a tight fit between the guide pin 128 and its mating component.

[0016] 1 , as anti-rotation device 130, lead screw 134, and piston 136 advance and retract within first passageway 114, they advance and retract along or parallel to body central axis 116, preventing binding or any increase in friction that would alter the motion of piston 136. Guide pin 128, having guide pin length 156, has guide pin cross-sectional shape 166. Guide pin length 156 is at least equal to the sum of displacement 199 and anti-rotation device length 198, but is no greater than first passageway length 193 to allow anti-rotation device 130 to move displacement 199 along guide pin 128.

[0017] Movement of the piston 136 is effected by movement of the lead screw 134 as a result of rotation of the rotatable hollow, internally threaded shaft 106, whether the rotatable hollow, internally threaded shaft 106 is mounted within the motor 104, at the end of a solid motor shaft 302 associated with the motor 104, or at the end 404 of a gear body 402 connected to the motor 104. To provide the rotation, movement, and displacement of the piston 136, the lead screw 134 has a lead screw thread portion 160 terminating in a lead screw rear end 172 with a lead screw thread length 152 greater than the displacement 199 to ensure continued engagement between the lead screw 134 and the rotatable hollow, internally threaded shaft 106 even at maximum displacement, and a lead screw body 162 terminating in a lead screw first end 170 opposite the lead screw rear end 172. The lead screw 134 engages the rotatable hollow internally threaded shaft 106 and is configured to remain engaged with the rotatable hollow internally threaded shaft 106 at each end of the displacement 199 due to the lead screw thread length 152.

[0018] Linear displacement of the lead screw 134, and therefore the piston 136, is enabled by an anti-rotation device 130 that moves with the lead screw 134 to maintain the lead screw 134 aligned along the body central axis 116. As shown in FIG. 1 , the anti-rotation device 130 extends from the lead screw 134 away from the body central axis 116 in the lead screw body 162 and includes a guide pin passage 132 having an anti-rotation length 198 extending from an anti-rotation device front end 196 to an anti-rotation device rear end 195. The guide pin passage 132 has a cross-sectional shape that matches the guide pin cross-sectional shape 166, and both cross-sectional shapes may be cylindrical. The anti-rotation device 130 may be attached to the lead screw 134 or may be integral with the lead screw 134. The guide pin passage 132 prevents rotation of the anti-rotation device 130 while the axially rotatable hollow internally threaded shaft 106 is rotating. Guide pin passage 132 is aligned with guide pin 128, and guide pin 128 is sized by guide pin cross-section 166 to pass through guide pin passage 132, which has a cylindrical guide pin passage cross-section 176, allowing anti-rotation device 130 to slide along guide pin 128. Guide pin length 156 is at least equal to the sum of displacement 199 and anti-rotation device length 198, allowing anti-rotation device 130 to move along guide pin 128 by displacement 199. Guide pin passage cross-section 176 is complementary to and larger than guide pin cross-section 166 to avoid interference, allowing guide pin 128 and guide pin passage 132 to provide movement guidance without unnecessary clearance. Thus, anti-rotation device 130 provides stability by raising and lowering guide pin 128 while advancing or retracting it with lead screw 134 relative to housing 102. The anti-rotation device 130 may include a low friction surface, coating, and / or bearing in the guide pin passage 132 .

[0019] The anti-rotation device 130 may be sized to slidably fit within the first passageway 114 to dampen vibration, and its shape reduces deflection that could cause the lead screw 134 to deviate from the body central axis 116. The anti-rotation device 130 may be cylindrical. The anti-rotation device 130 has an anti-rotation cross-sectional shape 148 that is a different shape than the first passageway cross-sectional shape 118, such that the anti-rotation device 130 is sized to fit within the first passageway 114. The first passageway 114 has the first passageway cross-sectional shape 118, and the anti-rotation device 130 has the anti-rotation cross-sectional shape 148 that is complementary to and larger than the anti-rotation cross-sectional shape 148. Thus, anti-rotation device cross-sectional shape 148 is sufficiently small relative to first passageway cross-sectional shape 118 to avoid interference, yet is sized to allow anti-rotation device 130 to advance and retract within first passageway 114 without creating unnecessary gaps, thereby providing a movement guide.

[0020] Thus, guide pin passage 132 surrounds guide pin 128 without interference due to guide pin passage cross-sectional shape 176, and anti-rotation device 130 moves within first passage 114 without interference.

[0021] If desired, a second guide pin 128b can be used on the opposite side of the body central axis 116 from the guide pin 128, thereby improving stability and reducing displacement and rocking. When a second guide pin 128b is used, the second guide pin 128b is attached to the body 108 at the body inner surface 164 parallel to the body central axis 116. The second guide pin 128b can have a guide pin cross-sectional shape 166 and a guide pin length 156. When a second guide pin 128b is used, the anti-rotation device 130 is provided with a second guide pin passage 132b therethrough, and the second guide pin passage 132b is aligned with the second guide pin 128b. The guide pin cross-sectional shape 166b of the second guide pin 128b allows the anti-rotation device 130 to slide along the second guide pin 128b without interference. Second guide pin 128b can have second guide pin cross-sectional shape 166b when second guide pin passage 132b has second guide pin passage cross-sectional shape 176b that is complementary to and larger than second guide pin cross-sectional shape 166b.

[0022] The lead screw 134 is retained along the body central axis 116, allowing the piston 136 to drive the piston driven device 103 with minimal misalignment, minimizing friction and deviations in forward or reverse speed. The piston 136 extends from a first end 170 of the lead screw 134 along the body central axis 116 and is sized to slide back and forth through the second passageway 120 and configured for attachment to the piston driven device 103. The piston 136 may be integral with the lead screw 134 or may be attached to the lead screw 134. The piston 136 has a piston length 174 that is greater than the displacement 199 so that the piston 136 remains at least partially within the second passageway 120 at all times, preventing the piston 136 from being fully withdrawn from the second passageway 120. To allow the piston 136 to move forward and backward with the required displacement, the piston 136 has a piston cross-sectional shape 144 that is different from the second passage cross-sectional shape 122 and is sized to reciprocate within the second passage 120 without interference. This allows the piston 136 to move forward and backward within the second passage 120, providing a movement guide without creating an unnecessary gap. The second passage 120 has the second passage cross-sectional shape 122, and the piston 136 has the piston cross-sectional shape 144, which is complementary to and larger than the piston cross-sectional shape 144. When the piston cross-sectional shape 144 and the second passage cross-sectional shape 122 are cylindrical, the diameter of the piston cross-sectional shape 144 is configured to be sufficiently smaller than the diameter of the second passage 120 to avoid interference.

[0023] 2, a rod-type linear actuator 200 is shown in which the anti-rotation device 130 engages an opposing second body 248. Rather than having one or more guide pins 128 on the body 208, the second body 248 can have one or more guide pins 228.

[0024] The body 208 is a structure that provides a connection between the housing 102 and the piston-driven device 103. The body 208 has a rear body surface 110 and an exterior front body surface 112, with the rear body surface 110 located opposite the exterior front body surface 112. To maintain a predetermined position, the body 208 is configured to connect to the housing 102 at the rear body surface 110 and to connect to the piston-driven device 103 at the exterior front body surface 112. The body 208 provides an interior space through which the lead screw 134, anti-rotation device 130, and piston 136 move or pass during operation. The body 208 has a first passageway 114 with a first passageway cross-sectional shape 118 that extends from the rear body surface 110 to the exterior front body surface 112 about the body central axis 116 and terminates at the interior body surface 164. The body 208 further includes a second passage 120 having a second passage cross-sectional shape 122 extending from the body exterior front surface 112 toward the body interior surface 164 along the body central axis 116, the second passage length 194 being less than the displacement 199. The second passage 120 provides a passageway for the piston 136, and therefore the second passage cross-sectional shape 122 is narrower than the first passage cross-sectional shape 118.

[0025] The second body 248 is sized to fixedly engage either or both of the body 208 and the housing 102. The second body 248 can be cylindrically shaped and can be received within the first passageway 114. The second body 248 can be shaped to mate with the body 208 and can be configured to prevent the second body 248 from rotating relative to the body 208. The second body 248 can have a second body keyway 271 on a second body outer surface 272 adapted to receive a key 280, and the body 208 can have a body keyway 270 on a first passageway inner surface 273 adapted to receive the key 280, such that the body 208 and the second body 248 are held together by the key 280.

[0026] The second body 248 has a guide pin 228 attached to the second body interior surface 264. The guide pin 228 is parallel to the body central axis 116 and has a guide pin cross-sectional shape 266. The guide pin 228 extends toward the body interior surface 164 a guide pin length 156. The guide pin length 156 is at least equal to the sum of the displacement 199 and the anti-rotation device length 198. The guide pin 228 has the guide pin cross-sectional shape 266 and extends the guide pin length 156. The guide pin 228 is coupled to a modified anti-rotation device 130 having a guide pin passage 132 extending therethrough. The guide pin passage 132 is aligned with the guide pin 228 and sized based on the guide pin cross-sectional shape 266 and the guide pin passage cross-sectional shape 176 to allow the anti-rotation device 130 to slidably move along the guide pin 228.

[0027] Optionally, a second guide pin 228b can be used on the opposite side of the body central axis 116 from the guide pin 228 to improve stability and reduce displacement or rocking. Optionally, the second guide pin 228b is attached to the second body interior surface 264 of the second body 248 parallel to the body central axis 116. The second guide pin 228b has a guide pin cross-sectional shape 266 and extends a length of the guide pin length 156. The second guide pin 228b is coupled to a modified anti-rotation device 130 having a second guide pin passage 132b extending therethrough. The second guide pin passage 132b is aligned with the second guide pin 228b and is sized based on the guide pin cross-sectional shape 266 and the guide pin passage cross-sectional shape 176 to allow the anti-rotation device 130 to slidably move along the second guide pin 228b.

[0028] Similarly, various modifications are possible. That is, the configuration in which one or more guide pins 128 are provided on the main body 108 can also be applied to the configuration in which one or more guide pins 228 are provided on the second main body 248. The axially rotatable hollow, internally threaded shaft 106 can be provided within the motor 104, at the end of a solid motor shaft 302 associated with the motor 104, or at the end 404 of a gear body 402 connected to the motor 104. The anti-rotation device 130 can be attached to the lead screw 134 or formed integrally with the lead screw 134. The guide pin passage 132 can be sized to fit the guide pin 128 without interference based on the guide pin passage cross-sectional shape 176 and the guide pin cross-sectional shape 166. The anti-rotation device 130 can be sized to fit within the first passage 114 without interference.

[0029] Body 108, body 208, lead screw 134, anti-rotation device 130, and second body 248 ensure that piston 136 moves linearly along body central axis 116 and avoid deviations that may affect the rate of travel of piston 136.

[0030] The terms and expressions employed herein are used for purposes of description and not of limitation, and there is no intention in the use of these terms and expressions to exclude substantially equivalent features or portions thereof that have been described or illustrated.

Claims

1. A rod-type actuator having a housing and a displacement for use with a piston-driven device, comprising: wherein the housing includes a motor driving an axially rotatable hollow internally threaded shaft located within the housing; The rod-type actuator is The main body and wherein the main body has a main body rear surface and a main body outer front surface, the rear surface of the main body is located opposite the exterior front surface of the main body; The main body is configured to connect to the housing at a rear surface of the main body; the body is configured to connect to the piston-driven device at an exterior front surface of the body; the body has a first passageway extending from the body rear surface toward the body exterior front surface about the body central axis and terminating at the body interior surface; the first passage has a first passage cross-sectional shape, the first passage has a first passage length that is equal to or greater than the sum of the displacement and the anti-rotation device length; the body has a second passageway along the body central axis from the body exterior front surface to the body interior surface; the second passage has a second passage length that is shorter than the displacement; the second passage has a second passage cross-sectional shape, The second passage cross-sectional shape is narrower than the first passage cross-sectional shape, The body has a guide pin; the guide pin is attached to the body at the body interior surface; The guide pin is parallel to the main body central axis, The guide pin extends a guide pin length; the guide pin length is at least equal to the sum of the displacement and the anti-rotation device length and is less than the first passage length; a lead screw having a lead screw thread portion terminating at a rear end of the lead screw and a lead screw body terminating at a first end of the lead screw; wherein the rear end of the lead screw is located opposite to the first end of the lead screw; the lead screw is configured to engage the axially rotatable hollow internally threaded shaft; the lead screw thread portion has a lead screw thread length that is longer than the displacement; an anti-rotation device extending from the lead screw body away from the body central axis; Here, the length of the anti-rotation device is the length from the front of the anti-rotation device to the rear of the anti-rotation device, the anti-rotation device has a guide pin passage therethrough; the guide pin passage is aligned with the guide pin; the guide pin is sized to pass through the guide pin passage so that the anti-rotation device can slide along the guide pin; the anti-rotation device is sized to be movable within the first passage; The piston and wherein the piston extends from the lead screw at a first end of the lead screw along the body central axis and is configured as an attachment to the piston driven device; the piston has a piston length greater than the displacement; The piston is sized to be able to slide back and forth through the second passage. A rod-type actuator comprising:

2. In the rod-type actuator according to claim 1, The body has a second guide pin; wherein the second guide pin is attached to the main body on the main body inner surface, The second guide pin is parallel to the main body central axis, the second guide pin extends the length of the guide pin; the anti-rotation device has a second guide pin passage therethrough; wherein the second guide pin passage is aligned with the second guide pin; the second guide pin is sized to pass through the second guide pin passage so that the anti-rotation device can slide along the second guide pin. Rod-type actuator.

3. In the rod-type actuator according to claim 2, the axially rotatable hollow internally threaded shaft is located within the motor, at an end of a solid motor shaft associated with the motor, or at an end of a gear body connected to the motor; Rod-type actuator.

4. A rod-type actuator according to claim 3, the anti-rotation device is attached to the lead screw; Rod-type actuator.

5. In the rod-type actuator according to claim 3, the anti-rotation device is integrally formed with the lead screw; Rod-type actuator.

6. In the rod-type actuator according to claim 3, the anti-rotation device has an anti-rotation device cross-sectional shape; the first passage cross-sectional shape is complementary to and larger than the anti-rotation device cross-sectional shape; the first passage cross-sectional shape is complementary to the second passage cross-sectional shape; The guide pin has a guide pin cross-sectional shape, The guide pin passage has a guide pin passage cross-sectional shape, the guide pin passage cross-sectional shape is complementary to and larger than the guide pin cross-sectional shape; the second guide pin has a second guide pin cross-sectional shape, the second guide pin passage has a second guide pin passage cross-sectional shape, the second guide pin passage cross-sectional shape is complementary to and larger than the second guide pin cross-sectional shape; The piston has a piston cross-sectional shape, the second passage cross-sectional shape is complementary to and larger than the piston cross-sectional shape; Rod-type actuator.

7. In the rod-type actuator according to claim 1, The anti-rotation device is cylindrical in shape. Rod-type actuator.

8. A rod-type actuator having a housing and a displacement for use with a piston-driven device, comprising: wherein the housing includes a motor driving an axially rotatable hollow internally threaded shaft located within the housing; The rod-type actuator is The main body and wherein the main body has a main body rear surface and a main body outer front surface, the rear surface of the main body is located opposite the exterior front surface of the main body; The main body is configured to connect to the housing at a rear surface of the main body; the body is configured to connect to the piston-driven device at an exterior front surface of the body; the body has a first passageway extending from the body rear surface toward the body exterior front surface about the body central axis and terminating at the body interior surface; the first passage has a first passage cross-sectional shape, the first passage has a first passage length that is equal to or greater than the sum of the displacement and the anti-rotation device length; the body has a second passageway along the body central axis from the body exterior front surface to the body interior surface; the second passage has a second passage length that is shorter than the displacement; the second passage has a second passage cross-sectional shape, The second passage cross-sectional shape is narrower than the first passage cross-sectional shape, A second body; wherein the second body is sized to be fixedly engaged with either the main body or the housing; The second body has a guide pin, The guide pin is attached to the second body at an inner surface of the second body, The guide pin is parallel to the main body central axis, The guide pin has a guide pin cross-sectional shape, The guide pin extends toward the inner surface of the body by a guide pin length, the guide pin length is at least equal to the sum of the displacement and the anti-rotation device length; a lead screw having a lead screw thread portion terminating at a rear end of the lead screw and a lead screw body terminating at a first end of the lead screw; wherein the rear end of the lead screw is located opposite to the first end of the lead screw; the lead screw is configured to engage the axially rotatable hollow internally threaded shaft; the lead screw thread portion has a lead screw thread length that is longer than the displacement; an anti-rotation device extending from the lead screw body away from the body central axis; Here, the length of the anti-rotation device is the length from the front of the anti-rotation device to the rear of the anti-rotation device, the anti-rotation device has a guide pin passage therethrough; the guide pin passage is aligned with the guide pin; the guide pin passage has a cross-sectional shape that allows the anti-rotation device to slide along the guide pin; the anti-rotation device has an anti-rotation device cross-sectional shape; the anti-rotation device is sized to fit within the first passage; The cross-sectional shape of the guide pin passage is larger than the cross-sectional shape of the guide pin, The piston and wherein the piston extends from the lead screw at the first end of the lead screw along the main body central axis and is sized to be able to slide back and forth through the second passage, and is configured as an attachment to the piston-driven device; the piston has a piston length; The piston has a piston cross-sectional shape, The piston is sized to fit into the second passage without interference. A rod-type actuator comprising:

9. The rod-type actuator according to claim 8, the second body has a second guide pin on the opposite side of the body central axis from the guide pin, the second guide pin is attached to the second body at an inner surface of the second body; The second guide pin is parallel to the main body central axis, the second guide pin has the guide pin cross-sectional shape, The second guide pin extends toward the inner surface of the main body by the guide pin length, the anti-rotation device having a second guide pin passage therethrough; the second guide pin passage is aligned with the second guide pin; the second guide pin passage is sized relative to the second guide pin to allow the anti-rotation device to slide along the second guide pin; Rod-type actuator.

10. The rod-type actuator according to claim 9, The second body has a second body key groove on the outer surface of the second body that matches the size of the key, The body has a body key groove on the inner surface of the first passage that matches the size of the key. Rod-type actuator.

11. In the rod-type actuator according to claim 1, the anti-rotation device includes a low friction surface, coating, or bearing at the guide pin passage; Rod-type actuator.

12. The rod-type actuator according to claim 8, The anti-rotation device is cylindrical in shape. Rod-type actuator.

13. The rod-type actuator according to claim 1, The second guide pin is located on the opposite side of the main body central axis from the guide pin. Rod-type actuator.

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