Bush hammer

A bush hammer is a masonry tool used to texturize stone and concrete. Bush hammers exist in many forms, from simple hand-held hammers to large electric machines, but the basic functional property of the tool is always the same – a grid of conical or pyramidal points at the end of a large metal slug. The repeated impact of these points into stone or concrete creates a rough, pockmarked texture that resembles naturally weathered rock. They can help to increase bonding effectiveness when applying new concrete to an existing concrete surface by increasing the surface area of the bonding zone.
Modern bush hammer.
The bush hammer has since been modernized in the past years, making it easier for the users to perform tasks while still having intended impression the tool gives. These machines are built to give the impression that a bush hammer has been applied to the concrete. This allows contractors to work on a larger amount of the material without using individual hammers for the project. This saves time and labor costs for those working with the tool. There are angled points that rotate to help imitate this tool. See figure 3 and figure 4. 
Inventor.
In 1831, Joseph Richards ( 1784-1848) invented the bush hammer or otherwise known to some as the axe hammer. The US patent was issued February 20, 1828 for a Stone-working tool, with a patent number of 5010X. Joseph Richards invention sparked many other inventors' designs for the bush hammer.
Similar tools.
The bush hammer is the patented title for this tool but has also been called different names over the years. The other most common name was the patent hammer which is described to have the same features and was used around the same time of the bush hammer. Another name this tool can go by is the axe hammer. This is due to the sharp conical edges the face of the hammer would contain.
References.
https://www.stonecontact.com/p/bush-hammering-machines
http://trowelcollector.blogspot.com/2015/12/joseph-richards-and-patent-hammer.html#:~:text=This%20YouTube%20video%20shows%20a,in%20Architecture%20at%20Archive.org.&text=The%20patent%20hammer%20was%20invented,patent%20was%20issued%2020%20Feb.
https://www.mainememory.net/artifact/19452