As opposed to the worm drive systems discussed here, a bevel gear system could be used to convert rotation to linear motion. This might offer greater efficiency to a machine screw jack because of it producing a rolling contact instead of the sliding contact of worm drive components. It could, however, come at a greater initial cost and will not cover as better ratio range as worm drives.
Also referred to as power screws, lead screws include several different types of thread profile which are suitable for different applications. Acme business lead screws are defined by their trapezoidal thread profile and 29° flank angle and are commonly within American Imperial machine screw jacks. An alternative solution to the Acme lead screw in a machine screw jack would be a square lead screw.
European or other international screw jacks utilise a trapezoidal lead screw with a 30° flank position and complies to an ISO metric standard.
Ball screw jacks require the thread of the business lead screw to get a profile that allows for the travel of the balls. To enhance load distribution and minimise put on, the ball screw track has a gothic arch profile.
Recognition of the trapezoidal screw thread comes from the fact that it is easier to machine and is therefore less expensive than sq . and ball screw thread forms. Additionally, because of the large area of contact between your business lead screw threads and the worm wheel, there can be a sizable load carrying capacity. This results in high friction which is certainly harmful to efficiency but does mean the system is more likely to be self-locking. This low performance means that such screw jacks are more suitable for noncontinuous or intermittent operation.
Many applications usually do not warrant the extra expenditure of a ball screw jack given that they usually do not require continual drive. In configuring a screw jack a prediction is made of the frequency of actuation which will point to the correct screw jack to end up being selected.
Translating Design Jacks are most often selected. With this design, a driven insight worm functions on an interior worm gear leading to the lifting screw to extend or retract. Operation requires that rotation of the lifting screw become prevented. This rotation it restrained whenever two or more jacks are linked with the same load.
Keyed Design Jacks are used any time rotation of the lifting screw isn’t restrained. For example, when you must lift the jack to meet a load. This is one way they work: An integral, set to the jack casing and inserted into a keyway milled in to the amount of the lifting screw forces the lifting screw to translate without rotating.
Keyed For Travelign Nut Style Jacks (KFTN) are another choice. These jacks have a fixed length lifting screw that rotates. Loads are mounted on a flanged “vacationing” nut that translates along the distance of the rotating screw. This type of jack is ideal for applications that cannot support a screw safety tube or that want a flush mount
The worm wheel acts on your golf ball screw (via the ball nut) which actuates the lead screw. This technique offers greater performance between the input and the useful output weighed against a machine screw jack. In addition, it allows for higher actuation speeds and, due to the low friction, is quite durable. Nevertheless a ball screw jack isn’t inherently self-locking and, because of its enhanced precision components, the initial outlay is greater. The resulting improved performance however implies this is often offset against smaller sized drive train components and a significant decrease in the necessary power.